The smart-tracker maker was one of four companies that testified against the big tech platforms - Tile focused on Apple - in a January hearing in Colorado of a panel of the House of Representatives Judiciary Committee.
At the time, Tile's General Counsel Kirsten Daru said that the company had initially had a mutually beneficial relationship with Apple which deteriorated last year amid signs that Apple planned to bring out a similar product.
"Unfortunately, since that hearing, Apple?s anti-competitive behaviors have gotten worse, not better," Tile said in a statement to the committee posted online on Wednesday.
Tile had objected to Apple requiring its users to repeatedly agree to allow Tile to operate in the background, which is crucial to Tile's service. Without background location access, Tile's app can only detect when a user loses keys or a wallet if they happen to lose it while the app is open.
"Despite Apple?s multiple promises to reinstate 'Always Allow' background permissions option for third party apps' geolocation services, Apple has not yet done so," Tile said.
Tile also said that there were indications that Apple planned to update its Find My product, adding hardware, so it would be a competitor to Tile.
Apple declined comment but pointed to a response it made to the committee in February which said that iOS 13 was aimed at strengthening privacy practices by reminding users that a third-party app is potentially using their location data.
Apple's Find My app enables background location tracking, Tile said, without these reminders.
Reuters reported in February that the U.S. Justice Department has reached out to app developers as part of its investigation into Apple.
The committee is one of several investigations underway into the big tech platforms, which also include Alphabet's Google, Facebook and Amazon. The investigations are being carried out by the U.S. Justice Department, the Federal Trade Commission and two groups of attorneys general from dozens of states.
(Reporting by Diane Bartz; Additional reporting by Stephen Nellis and Nandita Bose)