Underground oil tank in Newton NJ

I bought a single family house in Newton NJ at  action.com. After I completed the sale, I found out that there is an underground oil tank. I contacted EPA Environmental ( private contractor) to remove the oil tank. They asked for $1700 to remove the tank. After removing the tank, they pointed out that there are 8 holes on the tank and sent me a proposal for soil remediation for total cost of $8900. They said, will require to remove the contaminated soil having a subsurface evaluator look at it , taking six samples and sending them to the lab. Once EP has the results from the lab I should be  able to receive a no further action letter to close out the remediation.

I need an advice what to do. Any information will be appreciated.