Rent-A-Center

I want to know why I get approved and then I get denied with no explanation then I come back after I spend thousands of dollars with these people I went up and paid an Xbox off the last $400 cash after I paid 18 payments on it and they deny me two days before my kids birthday me with no explanation my credit should be good with you people while I found out that the guy who's running it up there don't look at anything I got approved how long ago and then you deny me and still haven't gotten an answer why I was denied it wasn't because the payments cuz you were paid off