Hi there! I'm also new here, but so far I've learned that you need that after completing an offer it is best if you keep the window open for a bit, and that helps with getting credited for having completing the offer. Sometimes still, you may not be credited, but usually you do. Keeping the window open longer and not closing it quick has helped, as I was advised on here. I don't know much about cashing out as I haven't done any myself yet. I'm sure the more experienced FusionCashers have more and better tips...
But, I hope this helps at least some...