False Facetime notifications

I keep getting Facetime Audio notifications from a cousin of mine at random times even though my phone doesn't ring. The notifications always come in pairs with the same timestamp. I thought my cousin was just playing around with me but I have received notifications when he is away from his iPod touch.

I have tried blocking his information as well as deleting him. I still get these phantom notifications. Does this happen for anyone else?

I am on an iPhone 5s on 8.1.1 but this has been going on since at least 8.0 or earlier, if I remember correctly.