Appalling quality!

Purchased several items from Gateway store KZN. Appalled to discover later that the ladies cotton sleep shorts ticketed together - both marked size S, one is in fact an M (has S size tag) and the pyjama set the top is XS which is what I wanted, but the shorts are in fact an L!! So i take the items back to the nearest store to me only to be advised i cannot return mismatched sizes to that store but i must take it back to Gateway 40km away from where i live. Why must i the customer, who has already been inconvenienced, now drive 80km to sort out their problem! Shocking quality and shocking in store service! For a chain that is struggling against Shoprite etc. they have no clue how to keep customers happy!