Old account needs to settled

Please tell me who is collecting your money. I owe woolworths some money and would like to pay them. I am getting calls from two companies claiming to be collecting my money on behalf of woolworths. All along MBD has been debiting my account and now they claim the account has been closed yet MBD debits my account. This is not on woollies. Please tell me where can I pay my account. The lady at the call centre could not answer me