call centre billing department

absolute sh!% experience, ive called in and spoken to 2 people, cant remember their names, couldnt help me, couldnt put me through to a team leader, manager, supervisor ect. that was on 29/12/17. today on 30/12/17 i called in and spoke to minenhle, senamile and daviyan and still the same thing, was on hold with all of them for atleast 10min each going up to 35min once, all in connection with the data charges for exceeding the 1gig. And i was assured it wont go over, and that it was limited to 1gig. Still no one calling me back, and could not even once get past the consultants. kept me on hold.