BAD BAD SERVICE

We have 2 cell phone and one 2 gig data card contract with Autopage. The 2gig data card has a standing instruction to suspend service (softbar) when the data usage exceeds 2 gig. In may we received an invoice on more than R3000.00 for data usage. We paid the monthly charge for the data card and the invoice amounts for the cell phone contracts. Now Autopage suspended service on all 3 contracts and can give no explanation for the data usage. We consider this as a breach of contract.