MBD STOP CALLING ME I OWE BRADLOWS NOT THEM

I have a credit with Bradlows which they handed over the account to MBD, however I contacted Bradlows via email confirming that I will start my payment in October which I have honour that agreement. An email was send to me including banking details which I used and deposited the money and will continue to do so. MBD they calling me every 2 minutes using 079 888.. and their office number, I told that person about my arrangement with Bradlows and I am paying. Can these organisiation back off anf leave my phone and space alone they are a nuisaince because I do not owe them any money my contract is with Bradlows not them. The irritate my skin.