I was evicted last July from my apt. If I moved out and my landlord gave me back 1500 in un-cashed cashiers checks (I owed her 2,000) Can she still legally send that amount to collections? My mother had co-signed the lease and collection letters were sent to her as well. I thought since I moved out and she GAVE ME back the cashiers checks, I would be absolved of this debt. Am I correct or do I owe the 2,000 + numerous late fees?

Yes, if you owed upnapid rent the landlord can try to collect it. They can refuse a partial payment.