I want my money

Hellopeter I used to have an account with Nedbank on January I went to the event somewhere and they asked if I can provide the banking details for payment and I gave them my Nedbank,I was waiting for my money to come in but nothing when I go to the branch they told me the account is closed and the money bounced back to the company.

I went back to the company they showed me prove of payment and yes it says payment successfully paid now I went to Nedbank so they give me a prove or a letter shows when was my account closed but they said they can't give me anything.what am asking my self is where is my money cause the company paid me and they showed me a prove what happened R2000 it's a lot of money just to give it to Nedbank for free please help