Bad service from Mweb.

Hi, i have a problem with Mweb, i recently ordered a connection with them cant remember the date but sometime May, the installer came and told me that because our address already has a fiber connection he will have to do some kind of a reapplication to say that the address already has a fiber and this one will be the second one, to this day that installer never came back, he was from open serve. i tried to call Mweb and let them them know of the situation and they said they will call me back, but they did not. i tried calling them again after i got a bill for the month of may to let them know that i did not receive any product from them or installation, then again i was told they will check into it, and now i got an SMS saying if i don't pay they will list my name with the Credit bureau, i called them and told them to cancel the order because they took time to get back to me and i moved on to other service providers.