What can ido if lawyer is withholding my share of settlement funds although ZURICH Insurance tells me check has been cashed $17,500 ?

I am assuming your claim involved medical expenses - if I am right then my first reaction is ten days for the attorney to have satisfied and obtained releases for all medical expense claims especially if any were paid by any government agency would be near record time.  Once a bit more time has passed I suggest you find your state's equivalent of what is here in Pennsylvania  the Pennsylvania Lawyers Fund for Client Security which acts on clients' behalf to recover funds a dishonest lawyer keeps from a client.  You might want to send a letter (not just call) to the lawyer advising him or her that if you do not receive your funds or a detailed accounting for the funds received on your case you will report him or her to the State Bar.  A lawyer can face serious discipline for keepinf client money so this threat will get his or her attention.