London-based Bloom had been placing ?2,000 worth of iAds per month since its launch last January, the company said, but the placements were banned earlier this week due to what Apple is said to have called a violation of internal company policy. News of Apple's action was first reported by The Guardian.
"They stopped us advertising a few weeks ago and we were unclear why. Then we received an email from our marketing agency saying that it was against their policy to advertise competing services," Bloom.fm marketing director Jon Clark told the publication.
"We're amused by this rather than frustrated. It's just pretty funny really. We're a tiny app, so we're surprised they even noticed what we were doing," he added.
The move has fueled speculation that Apple is preparing to roll iTunes Radio out to users in the U.K. The service is slowly spreading around the world, having launched in Australia in February.
Apple, meanwhile, is believed to have reached representation agreements with digital advertising agencies AKQA, Huge, Area 17, and Kettle. Those agencies would supplement the work of Apple's primary media partner, TBWA\Media Arts Lab, according to Advertising Age.
It would be Apple's second digital realignment in as many months after the company gained a dedicated studio brand from longtime partner Rosetta in February.
The new agencies' brief is expected to be "broad" and include user experience and digital strategy. Apple has been rapidly expanding its digital presence, running a well-received animated campaign for the iPhone 5c on popular web properties like Yahoo and Tumblr.