This is printed from the same files uploaded here. Some of the boxes I make are just tight fits and with the curves can just be a PITA to put together. Sorry you had issues with it. Anyway you could take some pictures of the issue?

i tried every way possible i got it almost all the way on in multiple positions but once you get to that last little bit it goes beyond the border of the box and definitely isnt getting pushed in. the main part that wasnt popping in at all nomatter what was V curve on the left side where the tip of the crescent is. and i do not i threw it out

Again im sorry you had issues with it. I was going to say if you still had it maybe i could resize the offset on the backplate for you and see if it would help.