Recurring data

Dear Sir/Madam. I have 2 sim cards *** and ***, which over the last 4 months have had recurring data added to my account. A few amounts of 20gig data was added, which adds up to thousands of rands and mys settings don't allow me to stop it. Its says contact your service provider. When I went to the service provider they couldn't stop it either. I submitted a query wrt the added recurring data and also the stopping of it. On 7/4/16 I phoned the 808 number and a lady manage to stop 2 of the recurring datas, but the others seem to have been stopped already. I inquired how this recurring data happened and was told it was a self service I added. I only buy data through FNB and not on my phone. My sim cards did not have the facility to purchase the huge amount and I was shown how to change the setting to purchase the huge amounts. I have never used those settings and on one of the sim cards, which is in my Ipad, I am the only one using it with a password. I would like MTN to investigate because I have never even seen those amounts of data or used it and would like a refund of the thousands of rands please.