Manager made broken promises

I submitted a complaint on Hello Peter to Dion Wired on 8 March 2016 regarding a disgusting phone call I received from one of the agents regarding my account. One of the managers then called me a day or 2 later who apologised and told me the issue was escalated and something will be done about it. We then discussed a payment arrangement for March and April and he advised that my account is still with them and that the next call I receive will be end of April. I now received a call from a collection agency telling me my account is handed over and demanding payment from me. So it seems the phone call from management was a waste of time and all promises made was not real. After I was made to feel at peace with everything, it was immediately destroyed again. I now have no idea if the story the manager gave me is correct or not