You sent Aunt Tilly a sweater for Christmas, but it never arrived. Uncle Bob apologizes, but no amount of shaking will induce ticking in the watch you gave him. Niece Susie wonders why her slippers, a Christmas gift, don't match.

Much goes awry every gift-giving season. What to do? Here are a few suggestions:

"Stores are not obligated to provide a refund and people often think they are," says Dave Johnson, vice president of operations, the Better Business Bureau of Metropolitan Washington. "It's up to the consumer to find out the company's policy.

"No law specifically addresses a refund-exchange policy in the District or Virginia," he continues. "Companies are free to set their own. In Maryland, stores must disclose it at the time of purchase on a sign near the register or on receipts." In Virginia, stores also are required to disclose their refund policy.

If you have a problem, "go to the manager. Don't get brushed off by a salesperson," he suggests. If you get inadequate redress, write the Better Business Bureau, 1012 14th St. NW, Washington, D.C. 20005.

If you are dissatisfied with an item you purchased in the District, you may file a complaint with the Department of Consumer and Regulatory Affairs, 614 H St. NW, Room 104, Washington, D.C. 20001 or call 202-727-7080 between 9 a.m. and 3 p.m. for a complaint form. This office mediates disputes using the 1976 Consumer Protection Procedures Act, which covers purchases of goods and services for personal household or family use.

"If mediation to settle the matter fails, then the case is sent forward for a complete investigation and enforcement action, including a hearing before an administrative judge," says Diana Haines, chief of the department's office of compliance.

Despite its name, the Automobile Consumer Protection Act of 1984, the "Lemon Law," can cover other big-ticket items, such as appliances and fur coats.

If you are unable to resolve a dispute, file your complaint with the Department of Consumer and Regulatory Affairs. The case goes to the Consumers Claims Arbitration Board. If the board decides a vehicle or other product is a lemon, it orders the dealer or manufacturer to issue a refund or replacement.

If the business with which you are feuding is not in the District, call your area's office of consumer protection (Maryland, 301-925-5100; Alexandria, 703-838-4350; Arlington, 703-358-3260; Fairfax, 703-359-9161; Falls Church, 703-532-1613, and Prince William, 703-335-7370).

If you feel you have been defrauded through the mail service, write Regional Chief Postal Inspector, Attn. Fraud Section, Eastern Region, P.O. Box 3000, Bala-Cynwyd, Pa. 19004-3609. Recount what happened, dates, manner in which you placed the order, and send photocopies of the front and back of canceled checks or money-order receipts.

The Federal Trade Commission's mail-order rule -- "the 30-day rule" -- protects consumers who shop by mail, but does not cover photo-finishing services, magazine subscriptions, cash-on-delivery orders, seeds or plants. Nor does it cover telephone orders billed to credit cards, but it does apply to telephone orders if the purchaser sends payment by mail.

A mail-order company must send ordered goods within the time specified in its ads or within 30 days if no shipping date is given.

If an item arrives damaged, call the customer service department (collect, unless it's a toll-free call) of the company that sold you the merchandise.

If you haven't resolved the problem within 30 days you can write to Direct Marketing Association, Mail Order Action Line, 6 East 43rd St., N.Y., N.Y. 10017-4747. Give details of the problem, the item or service ordered, the date of order and photocopies of material substantiating your complaint. Allow them 30 days to settle the problem with the mail-order company.

The Federal Trade Commission's Fair Credit Billing Act of 1974 covers phone orders using credit cards as payment. It also provides assistance in billing errors. You can withhold payment for the portion of charges related to the questioned items and the company cannot charge you interest or report you delinquent while the error is being investigated.

Contact the credit-card issuer in writing, since "calling doesn't preserve your rights," says Carole Reynolds, senior adviser with the FTC's division of credit practices.

Explain that you are questioning your bill and withholding payment for that reason. Include your name and account number and a description of the error on the bill (item, date and amount). Send it certified mail, return-receipt-requested, and keep a copy of your letter. Mail the notice to reach the card issuer within 60 days after the first statement containing the error was mailed to you.

During the holidays another FTC law, the Claims and Defensive Provisions of the Truth and Lending Act, may be helpful for purchases and returns of items exceeding $50 bought in your home state or 100 miles from your address.

For example, if you have a dispute about a gift's quality and if under state law you can raise those rights against a department store, then under federal law you can raise the same matters against your credit-card issuer.

For the FTC's "Holiday Shopping Tips" and "Fair Credit Billing" and other consumer fact sheets, call 202-326-3650 or write FTC, Public Reference, 6th Street and Pennsylvania Avenue NW, Washington, D.C. 20580.If your quarrel is with a bank, call the nonprofit Bankcard Holders of America in Herndon, 703-481-1110. "We are the only group that goes to bat one-to-one for consumers on credit issues with banks, credit bureaus or merchants," notes Elgie Holstein, the organization's director.

Visa, Mastercard, American Express and the AT&T Universal Card all provide purchase-protection plans to some of their members covering most items for 90 days after purchase against theft, damage and loss or accidental breakage. They also double the manufacturer's warranty for up to one additional year.

Mastercard even provides its 10 million Goldcard holders with gold stickers containing a toll-free hot line number. The stickers may be placed on presents so that recipients may file a claim for a refund or exchange without the embarrassment of telling the gift's buyer.