Missing screws for filament runout detector

I’ve tried going though support and have gotten nowhere in a month. When I received my new UpBox+ over a month ago, it would not print because of a no material error. After contacting support I was able to take the side cover off and found that the screws that are supposed to hold in the filament runout detector microswitch were never installed. They sent me a replacement switch but it did not come with screws and they refuse to answer my email asking for the type of screws I need. They told me to get them myself! When I replied that I needed to know just what size of screw I needed or where to get them I got no answer! I tried again and the same.
It’s been over a month now and I’m still printing with a jumper installed to bypass the switch. This is not good customer service and I’m very unhappy. Could someone tell me what size screws I need?