Still trying to charge us after we've cancelled ages ago

For many months since 2022, we had not been using Rain (discarded the sim card) because we were not getting good coverage. On December 2022, we were debited and amount of R2460 for the arrears. We immediately contacted Rain and requested that the officially cancel our subscription and they confirmed that they did. Fast foward to March 2023, we find out they have been harrasing our friends and relatives saying that we've been owing them money since 2023 and that they are looking for us. I did some searching on the internet and realised that many custoers are having the same issue. It seems there is no escaping them once you've signed up with them. This is a profound level of dihonesty in which to run a company.