If you still have an issue, let me know and I'll see if I can be of assistance.
I'd get a quote to have the hardwood floors buffed out and the walls repaired and would then contact the Sellers and speak with them about the damage and what it is going to cost to repair it. Hopefully their fair people and will send you a check, if not you may need to pursue them in small claims court. I would take pictures of the damage and hold on to the note as evidence.
Next I'd contact my buyer agent know that their refusal to even try to help indicates that they never really cared about you and were obviously only interested in the commission and that now that you understand their position clearly you wanted them to know that you will never recommend them to others and will in fact go out of your way to make sure others know that they aren't' really interested in their clients. It's certainly not their fault the Sellers damaged the home, and they shouldn't be expected to help pay for the damage, however they should have cautioned you about closing before the Sellers were out and they certainly could have offered to help you track the Sellers down so that you could speak with them directly.
But you may want to double check with your attorney.
Moreover, try to determine if pursuing the claim is worth your time and effort and money--there is a filing fee involved and perhaps--a laywer's fee for the consultation
It's worth noting that your agent's comment about how they "can no longer help" is troubling. I treat my clients as a "lifetime client" instead of a "transaction client". It's too bad that they're so quick to dump you off.
I'd speak to your agent's broker, who may be surprised or concerned at your agent's failure to protect you.
If that's unsuccessful, then you might try small claims court, seeking to collect from your tenants. You might include your agent in the claim as well.