Cell C
Garnished but account paid up

When I relized that I was handed over by Cell C, I made arrangements and the account was paid up but after a year I realized on my salary advise that I was garnashied they said that they never received any money and I tried to fax the proof of payment but till now I never received any answer they still insist that I never paid them I kept the receipts as proof of payment I still do have all the proof of payment filled. may u kindly help me to recover all the money that they pull out of my account as I have all the proof of payment