They say it has left them unable to access bank accounts and job offers - and stopped them using Skype, which Microsoft owns, to contact relatives in war-torn Gaza.
Microsoft says they violated its terms of service - a claim they dispute.
“They killed my life online,” said Eiad Hametto, who lives in Saudi Arabia.
“They’ve suspended my email account that I’ve had for nearly 20 years - It was connected to all my work,” he told the BBC.
He also said being cut off from Skype was a huge blow for his family.
The internet is frequently disrupted or switched off there because of the Israeli military campaign - and standard international calls are very expensive.
Israel launched its offensive in Gaza in response to the Hamas attack on 7 October, which killed about 1,200 people. The Hamas-run health ministry in Gaza says more than 38,000 people have been killed in the war.
Same as with your bank accounts, choose two providers.