I had to file a substitute w2 the estimated refund date was May 3rd why haven't I received it yet?

TT dates are just estimates, and only the IRS controls when you get the refund.

A substitute W2 means the IRS has to confirm with the employer why no W2 was filed. They will require the employer provide proof of filing returns and paying the payroll taxes required. (That's usually the problem, they didn't file because they didn't pay the payroll taxes)  It's not a simple procedure.

Hang in there.