MBD - Do not have proof of claims

MBD keeps contacting me regarding an alleged outstanding account. No proof or Statement of the Account can be given from the original Supplier. Upon requesting MBD to give a full and detailed account on where the amount comes from, I am told to ask the Supplier directly, since they only have a Balance that was taken over. If and when you want a person to make payment arrangements, for an alleged outstanding account, you need to be able to provide full details of the account that was taken over with proof thereof. I have a legal right to know where the alleged amount is coming from. Above all, and after explaining this on numerous occasions, they keep phoning me, reminding me that our calls are recorded. So I have now reverted the phrase back to them, reminding them of the recording and to refer back to numerous previous conversations. They normally end up by putting the phone down, and then getting someone else to harass you later. If you are Attorneys as you are stating, then please have your facts straight. Bully tactic won't work with me.