When icing someone, why do people delete their numbers? If they call you again, how will you know who it is or if you're not supposed to answer. You could potentially reply and start a whole whirlwind of drama all over again.
Personally, I just ignore and silence the notifications. After I've made it clear that I'm done with their nonsense first. There should be no mixed messages, but, bitches be crazy and come crawling back.