Hi @MissScarlet,
Thank you for your post and welcome to our Community Help Forum!
I am sorry about your issue. This may happen for multiple reasons such as your card has been previously registered on other PayPal accounts, it has exceeded the limits, our internal security system is blocking it. In addition, we limit the number of times a credit card can be added to different PayPal accounts.
If that is not the case, please try contacting customer service by phone by clicking Contact at the bottom of the PayPal website and then Call us, or reach out by PM on Facebook or DM on Twitter.
I hope this helps.
Cristina
