Dissatisfied with MTN Service

During sept and nov 2014 I did write to hellopeter with regards to incorrect billing on my data line, however after intervention from hellopeter a credit was done, but the overbilling continued from dec to now, I have been constantly contacting the call centre to resolve the matter or to give me the links that I have used but to no avail. During the strike period it was impossible to get any response from MTN, however my bill is currently almost R10000 and on 15 June 2015 MTN decided to suspend my line whilst in dispute and no resolution, my account was handed over for collection leaving me with a bad credit record. After contacting a MTN store on 15 June I was asked to pay R2700 to get my line re activated, the store could not re activate and from waiting for 2-24 hours for activation I had to wait for 4 days. Due to MTNs incompetence I have a bad credit record is this fair?