xfinity mobile website

I have gone to the website because I'm interested in getting an apple watch, and I also want to upgrade my phone. Every time I go to the website, it allows me to log in, choose the discount code for the watch, but when it attempts to go to the next screen it tries to access for a few minutes and then gives me an 'access denied' screen. The other is that occurs is I will be able to add a watch, or the phone to my cart and it gives me an error that I don't have enough lines to complete the purchase.