WIFI EXTENDERS EMAIL

So I received an email about two weeks after I started my services with Xfinity about a year ago and it said that they had did an evaluation on my home network to see if there were any dead spots in my home and that if there were any, we would be eligible to receive WiFi extenders at no extra cost. Well I’m guessing the test said that we were eligible for the extenders and I am just now finding out about the email. So I went back and checked the email and tried to click on the link to redeem them and it keeps giving me error codes.