Highly Dissapointed with Matrix Telematics

I had a Beami account 3 years ago, i settle my outstanding balance in full, I have the proof of payment but somehow they handed me over to Nimble Group and but i had paid Beami in full I dont owe them a cent. When Nimble calls me i tell them i paid Matrix but they ask me for a paid up letter i never got one because i wasn't handed over at the time and i paid the money directly into their fnb bank account. This is reflecting badly on my credit score, can you please remove my name from Nimble and clear my name