Cellc And Nudebt debacle

I was advised by cell c legal to pay my account using the following reference ********** 84. However i recieved another email from Nudebt advising me to use the following reference: ********** 4. I made the payment as per nudebt's advise but now they suggesting that i used a wrong reference and should have used the one given to me by cell c. I have proof of their emails. Now i am struggling to get a paid up letter. Please help.