Item frames not there in lvl 11

Since purchasing item frames in level 11 of skybocks 2 avengetech, not only are the item frames glitching and non-existent when you try to use them but they constantly appear back in your inventory no matter where u place them (ie another chest etc) and anything u try to put in its place in the inventory disappears including enchanted weapons etc. Finally, now everything I buy from the command /shop is glitching with exactly the same faults as the item frames. so another box in my inventory is now unusable if I don't want to lose the things I put in place of my purchases, for instance, I tried to purchase 2 diamond ore generators for 65K each and they show as in my inventory but are not there when I click on the inventory box where they are showing. This makes the game pointless as I cannot progress if I can make no more purchase

please msg me if u have had this problem and u know of a fix/solution that makes it playable again.