Can't change payment details

Hello Charmaine,
Thank you for contacting AVG Community Support.
We undersyand you are unable change your payment option. We'll certainly check and help you out.
In this regard, we would request you to reach our billing team through chat. They will help you to update your payment method. 
Visit support (http://support.avg.com/support_sales?l=en)to reach our billing team.
Thank you and keep us updated.

Why does the system not allow you to change your payment option.

Hello Charmaine,
Thank you for contacting AVG Community Support.
We undersyand you are unable change your payment option. We'll certainly check and help you out.
In this regard, we would request you to reach our billing team through chat. They will help you to update your payment method. 
Visit support (http://support.avg.com/support_sales?l=en)to reach our billing team.
Thank you and keep us updated.