Unaceptable clothing store

The T-shirts are of the worst sizes ever. At one shop the XXL is to large at another shop, the same t-shirt same XXL is to small. How is this possible ?? I tried to phone this morning on customer service - no ***and was sent from one line to another as I made myself clear what division and to whom I wanted to speak to. At the Grove mall in Pretoria they had all in colors in heaps except for navy blue. But to NO avail I was assisted...just "sorry"... At Equestria mall same ..."sorry"