Poor Customer service

I took a contract with Telkom earlier this year, I miss payments in May and June so in July I paid R1522,70 in Telkom account and sent them proof of payment which they acknowledged in receiving. However yesterday they sent me a message saying that I owe them R3502,70 and **** today they debited it. So I had sent them an email asking for clarity on the matter but they don't respond even the whatsapp number they provided as their customer service tool is not helping. I want Telkom to refund my R1522, 70 back to my account.