MDB tries to collect prescribed debt

My husband started receiving calls from a debt collector more than two years ago, claiming he owed Virgin Active money. Despite repeated requests for proof of this debt, which he didn't believe he had, and requests to speak to a manager, no one ever furnished proof or sorted out the matter. The debt has clearly been sold to another company, MDB, which is now trying to collect on a proscribed debt. He currently has a debt with Virgin Active, for R2000, which he arranged to pay back but then ANOTHER MDB agent calls him and hoodwinks him into agreeing to a debit order... but then he realised it was for the old, proscribed, unproven debt!!! This is disgusting, *********, and if this doesn't get resolved, I'll be reporting them to the ombud.