Pathetic service Albermarle Mr Price by the store Manager

Iv just experienced a disgusting service at this store Mr Price albermarle with the store manager, I went to exchange a gift that I was bought for but the sizes are big. So instead of exchanging the items for the correct ones, the store manager informed me that she will issue a voucher instead. I politely informed her that she can exchange them without issuing a voucher as I dont have a receipt because it was a gift & that I only need the correct sizes of the same item bought. She insisted that it's still to be issued on a voucher instead. She credited the items on a gift voucher & when she tried processing the gift voucher it kept saying voucher not found. She then told me the voucher is irredeemable could be that it's off line. I told her she can process them & exchange without crediting them on the voucher but she was mean & rude instead. I opted to pay the items via my MrP store account. She then said the credit from the items I wanted to exchange she will credit it still on the gift card. When I tried to use the voucher at another MrP the voucher is invalid. So must I now drive back to that Mr P so the voucher can be activated. The service & the store manager is utterly disgusting to say the least.