Where are my replacements? Or my money back???

I initially had a great experience with this company - Spent a great deal of money on purchases and they arrived on time etc. However, 2 items did not fit and needed to be returned for a larger size. The package with my returns in arrived at their offices on 29 April and since then, they have just fallen off the face of the earth and I cannot get a response or an acknowledgement of receipt or confirmation that replacements are on their way. They are sitting with 2 items of clothing, worth about R900, for which they have already been paid. I want my goods or my money back! Terrible service! I am not letting this go!!