Poor service and excess charges

I bought a Huawei Nova 10 in 2022 on contract. My contract was supposed to end October 2024. I was paying R460 per month. Close to when my contract was supposed to end I started receiving statements that I have to pay more than a thousand rands. I queried and only got an emailed response after 3 emails I sent asking them to call me. They said I have subscriptions and I asked cancelation and they never did. The funny part is that I have another contract and they refused to make it one contract since I also took an iPhone 13 on contract. They asked for proof that I sent them emails and I do. I cannot call them because they don't have a number you can call unlike other networks. Until today they want the subscription fees yet they never called after I asked for investigations to be done on my MTN account.