CSS Credit Solutions have no actual solutions

All I know is that I have submitted my payment agreement and Proof to MTN, along with multiple people at this horrible institution. Everything I had to settle with the final notice payment was paid in full with MTN, along with the individual at MTN whom sorted some miscalculation based on my cancellation written notice. I hate CSS Credit Solutions and Not a single person there has been useful even with Final payments attached in writing numerous times. They harass nonstop and I have the call logs with this +*** to prove the nonstop harassment. I have told the lousy people who do no research to call the very service provider they advised me to resolve the issue with. " i will escalate and contact you within 24 hours", then some other person is given my number to irritate me.