Overcharge for 10meg line which we do not have.We have 4meg speed

My husband Ian Norman Freeman ID nr ********** 062082.Has been overcharged for the past year.We were offered a 10meg line to test once the adsl was replaced with fibre,but after that we had the option to convert back to our 4meg uncapped voice line.Which we asked them to.Since then we have been struggling with our billing.Then it was fine for few months after Riaan van der Westhuizen at cape Gate Telkom assisted us.Now again at the beginning of this year we were billed for 10meg linr again which we do not have!!!We did a telkom speed test plus we did not change our package.So I spoke to agent Terese on Telkom chat and she claims our account is still on 10meg since 2016 which is absolute ********!!It has been confirmed twice before that it was coverted back to our uncapped 4meg.Now some idiot changed our account again.Telkom must please rectify this unforgivable error.They can contact my husband at ********** 323 and email **********