who should i take to court the sellers or the real estate office ?

Do not block the holes they are using to get in and out. You don't want them dying up there. A bat contractor will install valves, so that the bats can get out, but cannot get back in. We had a bat case once before. The bat urine would crystalize in the beams supporting the roof, and then melt and smell when the sun beat on it during the day. The roof and beams had to be removed by crane. Insurance for the seller and the seller's broker paid for it. The Seller's agent had washed the deck to remove the bat guano every time the buyers came out to look at the property.  Your legal damages for this are the difference between what you paid for the house and what a reasonable buyer would have paid if the bat problem had been disclosed. That might be less than what it will cost to clean up your house and repair any damage. If you actually go all the way to trial, that makes the case expensive, because you will need experts on how to clean up and repair the house, how much that will cost, and on how much the house would have sold for if the bats had not been hidden from you. We would not take on this case on a contingent fee basis. That is where the lawyer doesn't get paid until the end and then gets a percentage of what is collected, usually about 1/3. We would want $350.00 per hour and would expect to be paid each month for work performed during the prior month. We can talk about estimating how much it would take to get to the point where you could negotiate a settlement to pay enough for you to get the clean up and the most critical repairs done. Happy Turkey Day. Dana Sack