usd chq boucned after credit amt into my account

Dear Sir, We got a chq from one of our client in USA they send us the chq and we spose to send them the shipment by air. They send us the chq of usd 24500 and the same chq we deposited into our bank. After 21 days cooling period bank will credit the same chq / amt into our account. Now after 1 months they said the chq bounced due to forgery in the mean time we have purchased the material and send to USA after getting money credit into our account. Then how much bank will said that after 2 months chq bounced due to forgery. Whereas they have already credit the same chq / amt into our account before 1 month back. pls. do let usknow what should I do.