Pathetic service from Cell c

I recently took a contract with cell c. They are supposed to debit on 27th of each month. The month of June 27th they did not debitI called on a monday to ask why that has not heppand, they did inform me that the debit did not heppan and they do not know why. So it is not that there was no money in my account they just did not debit.on the next day they also did not debit I called three thimes more to query still the reason was the same they do not know why they did not debit their system doeas not give a reason. The last time when I called they told me they don't know why it didn't debit and on top of that Im now in arreas. This is the service I got from cell see as a new customer. I still have 18 more months to go what a bad start. Unprofessional. I CANT EVEN CALL THEM BECAUSE THEY BLOCKED MY NUMBER. I WONDER HOW AM I GOING TO CALL THEM. WHAT A SERVICE.