Barely a month after rolling out 3G wireless phone service in Santa Barbara, Cox Communications cut off the offering effective today. Faster competitors and a lack of the iPhone doomed the plan, the company said.

A local spokeswoman said that though the rollout in Santa Barbara was going well, a nationwide order to halt the wireless program came from the cable carrier’s Atlanta headquarters. Customers who signed up will have service until March 30, will be able to keep their devices without paying termination fees and will receive a $150 credit on their bills, the company said.

In a release, Cox said its “decision to no longer sell its 3G wireless service was based on the lack of wireless scale necessary to compete in the marketplace, the acceleration of competitive 4G networks as well as the inability to access iconic wireless devices.”

The killing of the program caps a series of costly missteps in the company’s foray into the wireless phone market.

Cox, the nation’s third-largest cable television provider, spent $550 million buying wireless spectrum in its various markets and planned to build out its own wireless infrastructure. But the company abandoned those plans earlier this year on fears that by the time it rolled out 3G services, competitors AT&T and Verizon would be deep into providing next-generation 4G and LTE services.

Instead, Cox opted for a deal to resell Sprint wireless services. The goal was to lure customers who were using Cox for Internet, cable television and landline services all the way under the Cox umbrella by bundling in wireless phone services. The company had reached less than half of its footprint, however, rolling out services in Virginia, Connecticut, Ohio, Oklahoma, Nebraska and several markets in coastal California.

In Santa Barbara, Cox would have taken on Verizon, AT&T, Sprint (which continued to sell services under its own name) and T-Mobile, which AT&T is vying to buy despite a lawsuit by the Justice Department. Verizon plans to roll out its higher-speed LTE services in Santa Barbara by years’ end, and AT&T expects to have its 4G upgrade rolled out by the middle of next year.