Recollecting already collected item

Firstly I ordered a 2000VA Mecer UPS on 28 October 2021. I have received the UPS in good working order and I am very please with it. Then they delivered a 2nd UPS, same spec. I notified them and 2 weeks later they collected it via RTT. Then I received a call about a week later that the box received was empty. But sounded that the issue was resolved. Today another courier arrived to come and collect the already collected UPS. I am sorry, but this is a really bad experience. This was for sure the first and last item that I purchased from PC Shopper. Original order number ***