Title says it.. Shop said the harmonic balancer was destroyed as well. So I have to replace that lower crankshaft gear right? It'll definitely pull off right?

The shop told me due to the nut being loose the crankshaft is destroyed and the engine is toast because of it. Can I really believe this assumption?

Please I need a answer. I have enough money to go to the junk yard and get one from a Lancer 2002 Lancer. I just need to know.

The car wouldn't start at this time. Nasty shakes to the engine and popping sounds when I attempted to start it. When it ran it did this.

I'd upload a picture if it let me
​​​​​​