I just started my own firm and applied for an EFIN in a timely manner. It's taking the IRS longer than expected to approve my application. I have several returns ready to be filed, but can't file them without an EFIN. I'm trying to find a solution for this issue, and it appears the only option would be to find a 3rd party firm to e-file the returns on my behalf. Could I use another firm's EFIN with their approval?