Bad service

In May i took a deal with Telkom Windermere and the deal was i was to pay R230 per month it was going to be data and a pocket router, i asked to be debited on the 5th of every month starting from the 5th of August, on the 31st of July they attempted to debit, i phoned windermere Telkom they said they don’t know they will follow up, on the 5th of August i paid what i was told i was owing, the following month September i was told i owe R451 coz the debit order bounced i phoned their call centre i asked the lady why they took such money she didn’t help me instead she cut the call, i let the debit order go through, this month again i have been told i need to pay R451 again, i have phoned today and the guy told me i owe more up to R700+ i asked from what and all over again its from the bounced debit order. I will be cancelling and reversing this debit order