Allen and Joan Ullery wish they had never gotten cable television.

Since the Silver Spring couple subscribed to cable in June, they have had nothing but trouble -- poor picture quality, billing mistakes, faulty cable connections and missed service appointments.

To make matters worse, they said, they can almost never reach the cable company, Tribune-United Cable of Montgomery County.

"Is it really worth all this frustration and aggravation?" asked Joan Ullery, 35, a medical secretary.

The Ullerys' complaints are echoed by hundreds of disgruntled Montgomery County residents who have subscribed to the 10-month-old cable service from Tribune-United. From the company's 11,414 subscribers in June, there were 3,744 requests for service calls, said George B. Rose, investigative counsel in the Montgomery County Office of Consumer Affairs.

Complaints to the consumer affairs office have been steadily increasing since January, with phone calls topping 170 in July, about 50 more than in June and 100 more than in May. Written complaints climbed to about 70 in July, more than 30 above June and more than 50 more than the office received in May.

"These are the most complaints we've ever had about an individual business," said Rose. "In the last two months, we've received more complaints against Tribune than we receive in a normal month against the entire automotive industry here."

Tribune-United officials acknowledge that the number of complaints has increased, but they said the ratio of complaints to subscribers has decreased.

"We have grown from 2,000 to over 13,000 subscribers, adding them now at a rate of about 3,500 a month," said Fern Krauss, spokeswoman for Tribune-United. "With a base like that, you would expect the raw number of complaints to increase."

On July 9 the Cable Communication Advisory Committee set up by County Executive Charles Gilchrist to oversee the cable business reported that "the quality of Tribune-United's cable service and its responsiveness to subscriber complaints now has fallen to unacceptable levels." Tribune-United works under a franchise granted by the county and is regulated by the county executive and the County Council, Rose said.

But Tribune-United officials have consistently said they are working to fix the glitches in the operation.

"I do not think we have an alarming number of problems," said Krauss. "It is universally true that any new cable system is going to have a certain amount of problems."

Tribune-United has recently hired additional employes to answer telephone calls, Krauss said. But county consumer investigators argue that Tribune's telephone service has not improved and some consumers are put on hold for as long as an hour. Service appointments are still being missed, and some problems that consumers have complained about repeatedly are still unresolved, Rose said.

"I was really disgusted with them," said Mary M. Neff of Silver Spring. "I stayed home five full days waiting for a service person to come."

In comparison to other local systems, complaints about Tribune-United's system are three times the number of complaints received by the Fairfax County consumer affairs office about its cable franchise holder, Media General Cable Co. Media General has 55,000 subscribers and receives 75 to 100 complaints a month, Rose said.

Stephen and Edie Meleski of Takoma Park discontinued their cable service after only seven weeks because of what they described as billing problems, poor picture quality and their inability to contact Tribune-United on the telephone.

"I was one of the first in my neighborhood to subscribe to cable," said Stephen Meleski, 35, a coal consultant. "I wanted cable for years. But I was very dissatisfied with the cable system, so as a consumer I had no option other than to cancel my subscription."

Meleski took off a day from work to get his cable service installed, and no service person showed up. "I literally had to run after the Tribune-United service truck, which drove by my house around 7:30 p.m., and encourage them to install my cable service."

"What you don't see is the number of times that the people who contact us for a service call aren't there when we arrive," responded Krauss at Tribune-United. "We don't know exactly how long a particular appointment will take, and sometimes we are overbooked. But we make every attempt to call people to change service appointments."

Homes are now being wired in the Bethesda, Rockville, Potomac, Wheaton, Takoma Park, Silver Spring and Germantown areas. The heavily populated southern and central areas of the county are scheduled to be connected by the end of next year, and the remainder of the county by November 1987. Tribune-United prices range from $1.50 a month for service with about 40 channels to $65 a month for all 10 premium channels.

Tribune-United is using a new type of cable system in Montgomery County, TRACS, which has been used only once, in Tampa, Fla. While a traditional cable system has a converter box placed near the television set, the TRACS equipment is placed outside either on the telephone pole or on a pedestal. Tribune-United's Krauss said that because the equipment is computerized and often located on utility poles, customers need not be inconvenienced by service calls.

Krauss says the TRACS system is more convenient and faster, but county officials point to technical problems with the new equipment. For example, it is impossible for consumers to use their videocassette recorders to tape cable programs while watching a broadcast program unless they install extra equipment.

"There are persistent and frequent technical problems that have cropped up in the system," said John Hansman, manager of the county cable communications office, which is engaged in performance testing of the cable system.

In an agreement reached with county officials in June, Tribune-United agreed to reduce prices in order to save the typical consumer between 30 and 40 percent a month and to make some technical changes in its operation, Rose said.

Tribune-United bested seven other companies for the Montgomery County franchise in May 1983. It was selected by Gilchrist and ratified by the County Council.