Has anyone with a 3 mobile contract had problem leaving & they don't process your cancellation requests?

I've been giving 30 day notices for the past 3 months that mysteriously never get processed. I don't have a phone. Don't use the service and they always seem to claim that I never made the request - even when their screen says I did. Has anyone else had a problem ending their relationship with 3? Is there some page somewhere I can add my indignant very affronted and annoyed voice to - that could persuade them to stop being so opaque in their dealings?