emails to me bounce back to sender. Last week Outlook sent a message to say working on account and trying to sync with mobile device but now I am not receiving emails

For the past couple of days, emails sent to me are bouncing back to sender.  Usually I receive up to 15 emails a day but today, nothing. Last week when I tried to log on to check my emails, there was a message from Outlook.com saying they were trying to sync mobile devices and gave regular updates. Since then it is not working.  I need my email! I think it is a Microsoft problem. Please help.