Royalties can we still get them?

So we recently found out we own the mineral rights that were leased out by the previous owner before he passed away and we have owned the property for over 5 years. The wells have been producing and over the last five years the royalties amount to 33,000 dollars so what are the chances we can still get the money that was supposed to be paid out since we did not have a clue that we owned them so there was never a change of ownership done and the only reason we found out is because we just recently started receiving tax bills from the county for the mineral?
Thoughts on this anyone?

Get a copy of the lease and read what it says about heirs, etc. I believe that if the producers cannot locate the mineral owners, then the payments have to go into a fund, for a certain length of time. For that amount of money, I think I would invest in a lawyer, to make sure that you get what you're due.