USPS

LegalZoom asked me to sign the SS-4 document for EIN confirmation and send it back to them, so I sent it to them via USPS first class mail.

After a week later, I emailed them only to find out they never received it... I asked them if I could just scan it and email it to them, and they said yes. So why didn't they just say that from the beginning?

I guess I'll never use LegalZoom or USPS for my business.