+_R10000 bill for 3 MONTHS-UNBELIEVABLE

for almost a year now my account is on avarage R2500 p.m . I already complain 3 times about this, but all they say it is data useage. I have 2gig on my phone and a vodacom wi fi router with 2 gig and telkom wifi with more than 12gig. I have tested this. Currently i dont use my phone as im not working now for the passed 6 months. And still my account is this high. I dont use my data and on my contract i can not talk more than 700min a month. I use my telkom lte wifi for internet and not my phone. it is thus impossible for me to pay so much ever month. It was usually about R 1300 p.m. And i get the same answer because they cant find any problem. Even the forensic department told me that. It cant be. I do not use that much data on my phone.<br> Can you please investigate and get behind the problem.