Where's my proof of purchase

I've been receiving sms messages from "sifcoretail" purportedly on behalf of Stuttafords advising that I have an outstanding balance and I should pay into *** Nedbank account with *** reference. I haven't had an account from Stuttafords sinec they closed shop in Cape Town and to my knowledge my account was paid up. I asked for an account to be sent to me listing items allegedly purchased resulting in said payment. I got sent a document indicating a balance (not even date of purchase) and more than a years worth of card fees but no items purchased, even though the card has long been destroyed and the business doesn't have a physical presence. Accounts also usually include payments received but none of that has been made available. With all the phishing and ***** around these guys are sending sms messages, threaten legal action but fail to respond to a simple request. I always overpaid Stuttafords and had a positive balance and I am now to believe that they waited more than a year to inform me that for the first time in my history with them I failed to pay my account, they didn't bother to send me an account and now expect me to just transfer funds and pay for a year's worth of card fees.