Poor Service

My debit order date was at the end of the month. i asked for it to be changed to the 7th and I was told it could only be between the 15th and 30th so I asked for it to be changed to the 15th. This request was made at the beginning of September. On the 30th of September my account was debited and again on the 15th. i reversed the debit order on the 15th as my account was already debited on the 30th. Om monday the 19th of October i received an sms to say my account was in arrears and my account will be suspended so I called CellC and spoke to an agent who informed me that a payment arrangement can be made and my lines will not be suspended. I received a call again from another agent who asked if they could redebit my account and i consented and asked for my debit order date to be changed back to the 30th. i was informed that this would be done. During the weekend i discovered that one of my lines as suspended, on calling CELLC i was told that it was an open line and therefore it was suspended. All my lines are top up lines so where did this come from. I have had my contract with Cellc for almost 16 years and to be treated like this is disappointing as this is the 1st time that happen