Poor service

Two days ago, I checked my balance and I had roughly 138MB of data. The next day, I checked again and it had all vanished!! I had not used any and so tried to phone the call centre. They did not answer their phones as usual. I then sent an email. Still waiting for a response. Today, I am unable to send any messages via my phone or make any calls. It wont even allow me to phone the call centre. I tried from a landline, goes dead. I have more than enough airtime and my MB are still missing. No one has bothered to get back to me. I am highly disgusted!!!! I cannot wait for my contract to end so I can change service providers.