COS h4 to H1B. Terminated immediately after approval. Status and Options?

Hi All,

I came to USA on H4, applied for COS H1B. It got approved on Oct 4th and the approval notice reached the employer on 9th Oct. The very same day the employer said they cannot offer me employment and sent me an employment cancellation letter. I did not work with this employer for a single day.  

It has been 3 days since they informed me about the cancellation of employment. I receive the approval notice along with new I-94 on 12th Oct and same day, I filed for I-539 COS to H4 by sending copies of my H1B approval notice and latest I-94.

1)      In what status am I in now?

2)     Will USCIS question my out of status?

3)     If I am on H1, is it ok that I filed for I-539 COS to H4 now. Or should I leave USA immediately?

4)     After COS to H4, can I change back to H1B when I find a new employer in the future or will I be subjected to cap again?

Please let me know.