*****ing airtime and forceful recharge of the unknown advances

It has come to my attention that Vodacom is recharging my number with airtime advances even if I never requested the advance to ***** my airtime. I want them to stop giving me their airtime advances because at some point I only see when recharging it sends me a message of paying for advances I never requested from them the likes of today, they say I owe R4.10 which I can't recall myself asking R3.00...it may seem little but to me is an inconvenience to keep such service provider ripping me off