Ruining my credit profile

I had a loan with you which couldn't pay after i lost my job.... The account was sent to mbd attorneys and i have been paying as per arrangement on time. But Bayport still updates my credit bureau as late payment whereas i pay MBD on time every month... I contacted them and they said its Bayport who updates on my credit profile. So what i want to know why are you updating wrong information on my profile because i do pay on time as per agreement. Please sort this out.