Bad communication

Dear CellC, it is with great sadness that I write to you. For many years I have been a faithful client until now. My debit order bounced but I was unaware. In the past, someone contacted informing me that me debit order bounced and I made the needed arrangements to pay the out standing. My main number was changed and I no longer received account notifications on my main line. Then, without an sms, phone call, I get a message saying I'm being handed over, then you cut my line off. How do the layers or legal team get hold of me if you cut my line? To add insult to injury, I emailed customer support and to this day have not received a response. Someone explain to me what I'm doing wrong