B/fwd row on customers sale tab

SOLVED

We have a couple of anomalies which have previously gone unnoticed.

They affect any customer that has had a refund. For example, customer A had a refund back in November 2015 (8 years ago) the value of the refund was £1122.64. If we look at the sales tab on the customer form, the B/forward row shows a value of £8981.12 in the payments column and the row for November for the current year shows a payment for £1122.64?

It looks like the value is being carried forward for every year since the original payment back in 2015 and still showing up as a payment in the current year? We cannot figure out why this is happening but a similar thing has happened with every customer that has had a refund.

If anyone could shed some light on this we would be very grateful.

These payment are shown as type SP.

Thanks

Geoff