Urgent question for Approved H1B reopen

Dear all

My company applied H1B for me this year and we got approval in May 2014. However revently I got the status update from USCIS saying my h1b has been reopened. The message is below:

On Aug**, we mailed you a notice informing you that your I129, PETITION FOR A NONIMMIGRANT WORKER, was reopened. If you have not received the notice within 30 days of the date above, please call customer service at 1-800-375-5283 for further assistance. If you move, please use our Change of Address online tool to update your case with your new address.

I am in OPT CAP GAP now.

My questions are :

1: Why Uscis reopen approved case?

2: What’s my status now? If it is pending, can I still work after OCT1 st. Since I did get approcal notice from USCIS in May

3: Can I do H1B transfer duing reopen status?

Appreciate if anyone can answer my questions

Saurabh, can you also help me answer thses questions?

It’s very urgent to me and makes me really feel upset. Thanks so much for your help!