Refusal to return goods

My mom purchased electrical items from build it in Pretoria to use in Giyani. Some of the items were no longer required so we took them back to build it giyani. We were told that we must return the items to build it Pretoria despite having the invoices and the items not being opened. This defeats the purposes of having a branch in giyani. The manager told us he does not take returns or exchanges from other stores , only items from his store. Surely this can't be right.