wrong ID

I have been having problems with iCloud for the longest time. I changed my appleID months ago, and that was applied to my itunes and icloud accounts--when I log into icloud on my mac, I can do so with the updated/correct apple ID. I cant on my iphone or iPad though. I also can't accept the new terms and conditions. The only apple ID that I get prompted to log in with is the old one, and I cant go in on any field and put the correct Apple ID in. This has been going on for months and I thought it would be fixed when I got a new iphone, but i'm still having the problem on my device. I've tried that "Find my friends" fix a lot of people were able to use, and that did not work for me.

Help!