ADT bad service

I have purchased an ADT alarm system which I installed at my house 4 years ago. I paid for an ADT technician to program the alarm, all worked well till recently. One of my sensors is tripping the alarm unnecessary. So I called ADT to help me to bypass that zone because I can't switch my alarm on and they have been breaking in around my house allot the past 3 weeks. They said they can't help me because I don't have an account or profile with them. I spoke to two different people they had the same stories. They just said sorry they can help me. I am a bussiness owner and in my point of view this is the biggest opportunity to acquire a new client. They didn't offer to say but "if you join us we can help or if you pay for a technician we can help". I mentioned exactly this to them and they still said sorry they can't help. I recon we can call that bad service.