Apple care plus isn't transferring over to my iphone PLEASE HELP.!!

My apple care plus for my iphone 5 isn't transferring over to my iphone 5 I got swapped out because I was having issues with my iphone I check online and it tell me the normal 1 year and 90 day coverage but I purchased the plan but it's not transferring over to my iphone 5 I got today whats happening somehow please help