Free DDNS Account not worknig after 30 days, how to fix problem

hi guys, I need your help I got Hikvision Cameras install in my Home, and I got free DDNS Account from no-ip website, but this Account not work after 30 days, and they send me a link every month to click on it to run account & stay,. If I forgot or not check my email for 3 weeks then my ddns account is totally disconnect.

So I like to know, how to stay on ddns account longer over years for free of cost.

Thanks for your replies.