DATA CHARGED BUT NEVER REQUESTED

I’ve been billed for 1GB data since January – September 2017, that's 9 months at R130.70 excl vat, for 1 of my numbers. the contract came to an end and it wasn't cancelled nor upgraded and all of a sudden 1 gb of data have been included on the contract and I'VE BEEN CHARGED FOR 1gb of data every month. I have absolutely no clue why the 1GB was included on the number as I certainly have not asked for the data every month. Besides, the number belongs to my son, who isn’t even in the country. Vodacom then replies and will credit me for 4 months, which is totally unacceptable. Vodacom is a total *******. Thanks Shamiel