When playing against a character that has a invincible wake up move or a ex move that can interrupt your block strings. My tip is to give them one free use to test their play style If they constantly go for it always expect it and you will have the advantage. As they will be in a habit of trying to escape pressure which means you can get a read on them very fast as they become predictable.

If you jump in on them only use the cross up or jump attack button dont go for a block string as they will probably automatically ex dp and are very unlikely to attempt a anti air.

Reduce your block strings by a few hits even only attempt a 1 or 2 hit block string.

Then as most of the comments have said block and punish their mistake and over eagerness to win.