Tables being cut off on phones

Hello.

I have a responsive theme and everything works great on phones and pc’s. The only problems is the tables get cut off. This has not been a problem before but I have now included WPMUDEV Membership and the registration table gets cut off, so the paypal button is not accessible. This is a nuisance as it means customers have to sign up on a pc so I could miss out on sales.

An example can be seen here: http://www.thetippingteam.com/register/?action=registeruser&subscription=6

Any assistance would be great!!
Thanks