My employment was recently terminated and I chose to cash out my 401K and I signed the paperwork waiving the 30 day waiting period. My 401K account was closed and the check, made out to me, was sent to my former employer, per their instruction, and it was received by my former employers. It has been over a week and I have yet to receive the check. It is a substantial amount. Is there a law against not giving me my money? Is there a certain time frame of receiving my money? Is there an entity I can call regarding this matter.
Thank you so much.

You probably alreay have the money, but if not, contact the company and get the check. They have no right to hold it.

I recommend you roll the money over into an IRA immediately, because you may end up paying up to HALF of the distribution in taxes if you do not.