Queries over H1-B Transfer and Employment

[abcxyz2017]

I came to U.S two years before thro' company 'X' from India. Couple of months before, I had resigned from company 'X' and joined to company 'Y'. Company 'Y' filed for H1-B transfer and I got receipt notice as well. After I joined to company 'Y', they kept me unpaid since 2 months. But employment has not been terminated. They are advising me to travel back to India with a promise that they will get project for me before end of this year in U.S. Now

I have the following questions.

 

1. How long I can stay in U.S without salary?

2. As per my current employer 'Y' advise, if I travel to India, do I need to go for stamping with current employer's 'Y' I-797?

3. As per my current employer 'Y' advise, if I travel to India, if the employer 'Y' terminates me at India, how hard it is to do H1-B transfer to come back to U.S without recent payslips (provided I have payslips till July 2017)?

 

P.S :: I am not sure whether my previous employer 'X' revoked my H1-B after I resigned from there.