I have used FIREFOX for many years and have account. Right now I am located in France but normally based in US. I have tried multiple times to sign up to FIREFOX / MOZILLA VPN but when I reach the pay page and enter credit card details it will not let me pay. I have tried multiple credit cards both American and European and all valid cards but the pay button simply won/t turn blue and allow the final step. Do you have any suggestions ? Thank you very much.