Thousands of victims of allegedly deceptive advertising who purchased Colorado land may be eligible for up to $14 million in refunds and canceled debts because of an agreement announced yesterday between the Federal Trade Commission and several companies.

In what could be the largest cash settlement in FTC history, Banker's Life and Casualty Co. of Chicago, 11 other companies and Robert Greenberg of Los Angeles agreed to refund paid for land in Central Colorado, in exchange for return of the land. Future contract provisions also will be dropped.

The purchasers are scattered around the country, with concentrations in Chicago, Texas and Colorado, the FTC said. About 75,000 arces of land had been sold through advertisments in national magazines and newspapers, according to Gerald Jaggers, a staff attorney for the FTC's Denver regional office, which negotiated the agreement.

The companies involved are enjoined by the agreement from misleading consumers in future land sales, a provision likely to affect sales activities in Colorado and Florida, where the companies still have land interests.

The companies are forbidden, for example, from making unsubstantiated claims that the purchase of a lot is a good investment, involves little financial risk or is a way to combat inflation or become wealthy.

According to Jaggers, consumers do not have to prove they were deceived in order to get a refund. He added that the agreement covers land purchases that were made as far back as eight years ago.

The ruling is unusual because it breaks new ground by holding Banker's Life, the creditor of the land-sales company, responsible for making sure that all rquested refunds are paid.

If all eligible buyers accept the offer, cash refunds will total about $8 million and canceled contracts will total about $6 million.

The original complaint leading to the settlement, filed three years ago by the FTC, involves charges of deceptive sales practices and overinflated land values at six subdivisions totaling nearly 150,000 acres in central and southern Colorado, which FTC documents claim have "virtually no use at present or in the foreseeable future." The land being sold as homesites or for resale investments was "not usable as a homesite."

Land sales by the companies reportedly brought in $60 million, the majority of it coming from out-of-state purchasers from California, Texas, Florida and elsewhere, where sales campaigns had been active. In Park County, where independent appraisals valued the asic lots from $450 to $900, lots reportedly were being offered for sale for up to $9,000.

The FTC case has involved thousands of private attorneys in Washington and elsewhere, including James T. Griffin of Hubachek, Kelly, Rauch and Kirby, the Chicago law firm representing Banker's Life and Casualty.

A previous agreement was turned down by the commission in 1977. At that time, Albert Kramer, director of the Bureau of Consumer Protection, did not recommend approval but has now reportedly added his signature to the new settlement.

The complaint filed by the FTC listed more than a dozen charges filed primarily against Banker's Life and Casualty (J.D. MacArthur, owner of the life insurance company, was removed from the list from his death in 1978), the only party to the suit with any substantial assets. However Banker's Life and Casualty reportedly did not own any of the property at the time it was sold and did not sell it, but sold the land to other individuals subsidiaries) who then sold the lots.

Although the respondents maintained their sales campaigns were not deceptive and deny all charges, the FTC disagreed, listing in the complaint that the lots were being sold at inflated prices and offered with no assurance of water, acceptable road access or electrical service.

The FTC suit argued that the lots were not usable as homesites because of the unreasonable cost of utilities, the difficulty in obtaining home construction financing, the remote location and poor quality of the land.

An issue not raised in the case, and of particular significance for the subdivision in Park County in central Colorado was whether the land was sold without mineral rights in a region of uranium-ore deposits. CAPTION: Picture, At least traffic's not a problem at this corner in a remote area of Colorado that the FTC cosidered "not usable for a homesite." Federal Treade Commission