Why is your website so slow?

The xfinity site has always been bad but is getting worst and worst. I cant even make a simple payment. The website is super slow. I click to make a payment and the window just stay blank.

I never have any issues with otehr sites but always, always have an issue with xfinity site. You really need to fix this. The service is terrible. Then you call to make a payment but you only get as computer talking saying to go to the website to make a payment. Is really the worst customer service I have expierence from a company.