Useless RETURNS service

This complaint is about terrible RETURNS service! I have returned a faulty Mecer UPS for the 2nd time now! On the first occasion the return and repair took over 2 months to complete (partly due to a poor product and poor support from the supplier, Mustek). The repaired product lasted only a couple of months then failed again with the same fault. Still under warranty, I have returned the product again and last received any communication 2 weeks ago. I get no reply to my emails and the customer care number is never answered!! What more must one do! This product is necessary for power backup for my P/c's and now we are back into load shedding again...... So frustrating dealing with a useless organisation that has no clue as to how disappointing their customers experience is, pathetic! Order No #***4 and Ref: MRRN-MV9OW-PNAV