Horrible Service

Hi there last year Feb 2019 I was due for an upgrade . I took it and thats when my trouble started . I`ve been billed for an extra device R699.00 since . November I finally went into the store to try and sort this out . About R 4000 odd was transferred back into my account instead of R 6291.00 ... Ive checked both statements Dec, Jan , Feb statements the R 699.00 still appears . It`s been almost a year and the matter is still unresolved . I've called the call centre and I hardly get any assistance . They're rude and unhelpful ... I need this matter sorted urgently . I have been with Telkom for 6 years now - 3 lines .