dissatisfaction service provider

I am writing this to express the poor service I received from vodacom service ,As i have an contract with vodacom the service been provided to me is dissatisfaction, there was no single month that i have skipped ,Hence this morning the debit of R247 it was went through without any agreement or communication with me.....the R160 it was paid via EFT on the 30/07/2020 ,All amount debited to me its R407.00 ,and also the 2GB was added on my account without any formal agreements while there was no authority to deduct because my account its up to to date and our contract says the amount of R149 its payable monthly ....Surprisingly i dont know how does vodacom system worked .please i need my refund of R257.00 ,My reference query ***