If you have a case number and the Priority Date is current then contact NVC for a fee bill. Otherwise just call NVC for status.

Not sure why it was cancelled but normally if you are in status you can apply to change status.

Can I petition my son who is a Haitian born living in Santiago Chile to the Unites states?

If he is legally living in Chile you can select that consulate for him to process at. Is he over or under 21?

What will be my h1b status when sabbatical for 10 months?Will it affect the total 6 year max out of h1b?

As long as you request the leave of absence then you will maintain H status. This is a longer leave than I have usually seen approved though. If...

Getting a F1 visa while married to a US citizen

In theory yes but technically the F-1 requires nonimmigrant intent which is hard to prove after being married to a U.S. citizen.

H1B Extension

Yes this is doable provided status has been maintained.

Should I fill out the form I-539 twice to apply for both change of status and extend my stay in USA?

yes if COS is not approved before the B-2 status expires.

Can I work in hospital as volunteer?

Only if the position is one which would not normally be filled by a person being paid.

Should I go ahead with this plan and get my stamp?

I would get a Haitian passport and replace your green card. You can also make an INFOPASS at the local office to inquire on the status of the...

Can I get child support for my baby?

You need to check with a family law attorney on how to get support. Getting support by itself won't get you deported.