worst service ever. no communication what so ever

i signed up to supersonic in December, vumatel was closed for the holidays, so supersonic gave me a "loan" Router with LTE Sim card in it and stated that I would not have to pay for the service until I am fully linked with my fibre line. they then proceeded to charge me for the time I was using the LTE router anyway. after so many calls supersonic told me they would credit this for me. this credit never happened in almost 2 years now. this morning I woke up and my line was suspended. I phone in and super sonic tells me but my line was booked for suspension and that is right??? I asked them to do a recon and they told me i am behind, after using up all my airtime I found out that it is the credit that is still behind, nobody sent me an email on this, i did not receive any sms or message or communication of any sort on this. they just cut my line off. they are now refusing to switch on my line until I pay for the credit that is owed to me??? this is totally unacceptable as I followed all the correct paths to get my account sorted out, nothing ever happens, I just get told on the phone that the credit will happen and it just doesn't happen. next problem with super sonic is that they only send invoices when they feel like it. I receive a invoice from them once every 3 months about? what is going on in your finance department? now I get penalized for supersonics mistakes? unacceptable. I hope someone contacts me with someone authority, otherwise supersonic can know that I will not pay a cent further on this account and remove all their stuff and cancel everything with them.