I need help with fixing my chi straighteners!?

So, i had 2 chi straighteners. I've had them for some time now. Nothing is wrong with them they're perfectly fine. When my first straightener broke, i was using it and when i turned it back on it wouldn't turn on anymore. Then i notice some kind of crack on the plug. that's the only problem i saw with it. then now my other chi straightener broke and the same thing happened. I was using it and it was working then later on when i turn it on again it wouldn't turn on. then it had like a crack on the plug part as well. Please help!! Dos anyone know any trick or how i can fix this. This is the second in a row and chi straighteners are expensive i just really don't want it to go to waste like that. Especially when it's still perfectly fine and good condition.