You have proof in the form of invoices from the utility company that they didn’t pay them and you did. 

Where do I need to send an invoice?

They sent the $6300 cleanup invoice on May 12 (3 days after the end of their service).

If you can verify the funds you used for Y (HUD showing cash-to-close, receipts/invoices from contractors, etc), you may be able to get Y back as "cash-out" if you are at a very healthy LTV. 

The actual rules are quite complex but you get the basic idea.So keep all your receipts and invoices from 2016, but they won't apply until 2017 taxes.

I would suggest creating a new bank account just for your rental related activities.I would also suggest doing the same for a credit card.I would also suggest having an online storage app such as google drive, apple drive or dropbox to help save your receipts / invoices.

Enter a maintenance request, assign a vendor, attach a fake invoice.

Enter a maintenance request, assign a vendor, attach a fake invoice.

Enter a maintenance request, assign a vendor, attach a fake invoice.

*I will add, it's noted as due payable upon delivery, it's not a pay-n-wait-n-see thing.But for, say, a $145k multi-scope "flip", there will be a detailed invoicing schedule of a deposit for commencement of job, typically 10%, with achievement markers for next invoicing.