Should i have to pay for tuition?

I recently got fired from CR England after driving for a little over 5 months. My contract with them was for 6 months which was reduced from 9 months because I am prior service military. So I did not fulfill the full 6 months of the contract. They paid for my truck driving school which is good. But I just received a notification along with payment receipts stating that I owe them money for tuition. The amount owed is roughly $2400 which is a mark down from the $6000 that was supposedly paid for tuition. They must have prorated it based off of a 9 month contract. My question is, should I have to pay anything at all given that they terminated me? The reason for termination is understandable since I got into 2 DOT preventables in a 5 month stretch. But had they never fired me, I would have fulfilled my 6 months at which point I wouldn't have owed them anything. So I am wondering if their decision to terminate me might void the contract, and if I should have to pay the prorated rate at 9 months or should it be prorated at 6 months?

 

Are you affiliated with CR England? Lol.

 

I'm sure they have their arguments.

 

But I would have fulfilled my contract had they never fired me. It was their choice to terminate me. Not mine.