Roaming charges when not activated

We went on a trip to Botswana and did not call in to activate roaming. On our stay I used the lodges wi-fi with a pin received from them. Made no calls. I noticed the amount on my phone due was over R5000.00. My Husband whom the contract belongs to called customer service where the lady said she does not see anything on her side. When the statement came my husband called in again. Queries were logged and we received sms's with reference numbers(25/06/2015 - *** / 03/07/2015 - *** / 06/07/2015 - ***) but so far no one has resolved our problem. My husband also told them that when he is not reachable that they speak to me. The one time he was told that they cant find proof for the amount and he asked how they can bill us if they don't even know. The total for my account is R6566.01 of which R399 is for my monthly charges. I have made payment of R400 for that. In the meantime we received an sms that my service will be suspended today, 09/07/2015. As we have been trying to get this matter resolved I am unhappy with Cell C for suspending my service when they are the one not giving us service with this problem.