Radio interference between different channels
Dazzler_BE if they are complaining about TX interference this would normally be controlled and policed by a government department, check with who ever issues licences for radio spectrum usage.
Not sure about your country, but we are secondary users in the US and Australia and we can be stopped from using our equipment at any time if we interfere with any primary service.
The second issue you may have is the flight path, I have heard of police stopping people from flying kites because they show up on air port radar and the air space around all airports is controlled space.
Ether way you are possibly screwed, I would speak to them and find out what the problem is, you may find they only want to limit your altitude or the direction you fly in.
Good luck, let us know what the outcome is.