This is a personal finance issue. Nobody here can really provide any help. You should try to get a credit report and see what is going on in general.
For some reason, Synchrony bank will not allow you to have the "loan" of easy pay.
Were any of your Q easy payments late or forgotten? Did you move and change addresses so they do not have a credit history yet at your new address? Do you return a lot of items? Have you ever bought an expensive item from QVC before and paid it off?
Have any retailers or others reported you behind on any bills? Did you miss any payments? Are you on time with major bills like mortgage, car payments, etc. (bank reporting). Have you made a lot of big purchases recently and extended all your credit lines?
Please note, I am NOT asking you to answer these questions online. I am just sharing the possible reasons why there may be financial cautions associated with your name.
Yes, technically they can run credit checks on you every time you apply for easy pay. Something made a flag appear for your order.