POOR "RETURNS" SERVICE from BUILDERS WAREHOUSE

I bought an item for my swimming pool filter on Friday 8 Sept 2023 at Glen Eagles. When I tried it on my pool filter I saw it was the wrong size thread. On Satuday 9 Sept I took it back for a credit. The lady in the Returns office processed my return and stamped my invoice "Refunded". I asked for a reference number but she said it was not necessary as she has updated the Builders Warehouse system to pass a credit and that I will see it in my account. Today is Monday 11 Sept at 13h00 and there is NO credit from Builders Warehouse. I think the "Returns" service is very bad.