I had a valid B1/B2 visa with multiple entries valid for 10 years. I visited US for a business trip back in August 2010 and was given I-94 with six months stamp. Due to business reasons and due to my health reasons I returned back to India in Jan 2011, i.e 5 and a half months(less than the allowed 6 months). US Embassy in India contacted me afrer 1year and 2 months asking me to submit my passport. When I visted the embassy they asked me the reasons of my stay extending 5 and half months. I tried my best to explain but my visa was cancelled(no specific reason was given), possibly because they suspected that I was working on B1/B2 which was not the case.

Now what are the implications of this cancellation. Can I never apply for B1 again or for any US visa.

If I can apply, then is there a time gap required before I apply again. Does this cancellation mean that my future applications for any US visa(be it H1/L1/B1) would have much greater chances of rejection?

Can I put my case to embassy again as I am not sure why my visa was cancelled. Can this cancellation be undone?

Can someone share a similar experience or provide some knowledge on this matter