How do I get my 401K from my previous employer but keep getting excuses?

I do not know the answer, I do not know what law. You should submit the request in writing, on a form provided to you. But, it is likely the form will come from the administrator of the form, some one like Fidelity Investments, and not from your employer. It is likely you are not asking the right person. You should be aware that any 401k withdrawal is taxed in the year you withdraw, and if you are under 59.5 age, there is a penalty for withdrawing. You should seek the advice of a trusted tax advisior.

Report your employer to the IRS.

Contact the federal Pension Guaranty agency. Or an attorney if needed.