H4 EAD approved, never got the EAD

[dsrini]

I had applied for EAD card renewal (i765 with AR-11 (for address change)).  I have got the approval, but I am yet to receive the EAD card. Creating a service request with USCIS got the following response - "EAD card was returned undeliverable, will resend the card to new address within 45-60 days".

Now, it's more than two months from when I received the above response.

I created another Service request, but confused on how to proceed further -

1. Can I can re-apply i765 for Replacement card. If I do that will a letter explaining the above suffice (with service request response,Approval notice) for a fee waiver?
2. I was previously working in a firm A, but have quit the employment by previous EAD card end date. Now, I have a prospective job offer, can I start working for the new employer?
3. Can I start with my new job at the least after the new i765 (for Replacement) receipt ?