contract billing

I have been patient with Cell c and it seems like they will forever give me problems. I took a phone contract with them and they delivered two phones instead of of 1. I immediately called the sales lady(MONICA QHENKOANA) and informed her that they had delivered an extra phone. That was in April. they deducted their pro- rata both twice which was R39 x2, in May I was debited R358.02 and I again in June you debited R358.02. you have only just sorted now in July and you have an audacity of refunding me R212.75.... You were supposed to refund me R397.02. If you cannot refund me what is due to me, then it means your agents are doing this deliberately in order to rob clients their hard earned money.