Runway not collecting returms

I bought clothes on myrunway, the order was delivered however the shoes were small had to do a return them. I log a return the parcel took forever to be collected but I ordered something else so when the driver came to deliver a new order I gave her the return it is almost 4 weeks no refund ,no feedback from runway I have sent over 14 emails still nothing .have been corresponding with Channel who is now on mute