Former bank about to pay my property taxes.

[Lucky B.]

I recently bought a REO property about 2 months ago and yesterday I received a tax bill from the tax collector regarding the annual property taxes. On the bill it says , the former mortgage company has requested a copy of the bill. I called the tax collector office and ask them why is the former company getting involved with taxes, it is my responsibility now . She did not know the answer but told me to call Nation star mortgage and find out from them. I called and was on hold for 20 mins to the point where I got angry and just hanged up the phone because why do I have to waste time on this matter. I will pay my bill at the end of this month, but I am just curious to know what would happen if they mistakenly paid the bill before I do?