Paying undelivered service for over a year.

August 2023 I took wifi contract at telkom which came with router, I left the country in October and after that the router never worked though they kept on debiting my account, I went back to SA in April and tried to resolve the issue and they told me I had to pay a certain amount then I'll be connected within 48hrs, 72hrs passed and I was never connected, when I went back to the branch in Southgate the manager told me she'll book it in. Indeed she did and I gave her everything,router with the cord and Sim card. They brought back the router and unfortunately I had left again, but then the cord and Sim card weren't there, we asked I'd there's a way of doing Sim swap but they said no, they need to investigate the missing one, told my sister they'll keep her posted but never did. They had stopped debiting my account till few days ago they took over R2500 from my account, I can't reverse the debit order so basically for the past year I've been paying for something I never had. I sent 2 emails to their head office already but no response and I'm only coming back to south africa in February.