When I try to change it to numbers instead of months it won’t let me for payment

when I try to change it to numbers instead of months  it won’t let me for payment 

I cloned your form and I was not able to replicate the issue. I also noticed that the Expiration Month is not in numbers. I have cleared your form cache on our server. Could you please use the Test Mode when testing your order form? 

Let us know how it goes. Thank you.