27 years of direct debits

A question about : 27 years of direct debits

This is probably a non starter, but...
I am executor for my late father's estate.
Whilst going through his papers I found a credit agreement dated 1987 for the purchase of a water softener.
The agreement was for 36 months of Ј17.42 payed by direct debit, giving a total of Ј627.12.
According to his bank statements this amount was payed every month until his death last year- giving a rough total payed of Ј5644.08 (27x12x17.42). An overpayment of over Ј5000!
Is there a cat in hell's chance of getting the overpayment repaid?
Anyone care to calculate the total with prevailing interest rates/inflation?
Ta.

Best answers:

• Are you sure it was a DD and not a standing order?
• Just checked; it was a standing order.
• You might be able to get the sum paid back but expecting interest on it bearing in mind a standing order was under his control not the credit company might be pushing it. For all we/you know they may have written to him from time to time telling him to stop paying.
• Does the company that sold the water softener still exist?
• The interest calculation is purely academic.
  TBH I have little expectation of reclaiming anything...
• The executor of the estate can contact the company and make them aware of the overpayment. Then you wait for a refund. There are steps after that but you must give the company a chance to investigate first.
• Executor invoices the company directly for the over payment value.