MTN AND MONDO taking me for a ride

my nightmare begun when i app**** for the home router date for month to month on the 24th of may 2023,i was advised to pay an upfront fee of R325 which paid and i was advised my debit order will go off on the 4th of each month with a fixed amount of R249,to my suprise on the 4th an amount of R562 was attempted to be debited which is incorrect as i was supposed to be debited with only R249,SINCE YERTERDAY i have been calling the contact centre where i get sent from pillar to post by the caller centre agents who are very rude and not helpful and they just give me diffrent numbers to call or transfer me without even saying anything,still i havent got any assistance and dont know who to speak to anymore,what a pathetic service and disgrace for such a big company to treat their customers like this.my contact is *** i need help urgently