Account issues ipossible to rectify

I have generally had good service from Teljoy, though the past couple of months I have been having a hard time.

In September 2019, I had completed my previous term with Teljoy at which point one of their consultants called me to offer new products. I then app**** for some new products on a new term and took ownership of the old ones.

For the past couple of months they have been charging me for the old products which I should not have been. I have paid them more than I should as they kept telling me my account was in arrears.

I tried on numerous occasions to get a statement, as I don't get sent any form of invoice or statement, and after the 3rd time and threatening phone calls I finally got one

I reviewed my statement and then noticed the discrepancies. What I also noticed is that they know they are over charging me as some months they have credited the amount they over charged. I tried calling and sorting the issue out telephonically, but it is like talking to a brick wall. They keep telling me that my account is in arrears as my account is paid back dated and I should pay a month in advance.

They need to refund the money I have overpaid for the products I have taken ownership of and clear my account as I am not in arrears and have been paying monthly as I should.

Hopefully this will work as calling or emailing does not. Teljoy, please sort my ccount out!