Bad customer service from African Bank

I have loan with African bank that they decided to sell my debt to Nimble Group my debt it's not decreasing@all instead it's standstill wherelse I keep paying what is worse nimble charges for emails that I didn't even ask for I pay R950 but it's going up due to emails that I didn't even ask for why did they sell my debt to unprofessional company that can't even communicate with customers..