Sorry, it doesn't sound like there is an easy way out of this, especially because you have to deal with Sharjah authorities. I think these are your possible options.
1. Sharjah immigration - keep trying to talk to different people until you find someone there to help you. But immigration departments anywhere in the world are more often unhelpful than helpful.
2. The company PRO that got the ban lifted.
3. Someone else with enough wasta to overturn the Sharjah immigration decisions.
4. Maybe a lawyer if you can find one who finds a way that the authorities have not followed correct legal procedures. But that will be expensive.
5. Your embassy but embassies are not usually helpful with immigration issues.
6. You could try the Dubai residency department but as you came in through Sharjah, they probably can't help.http://www.dubaifaqs.com/dnrd.phphttp://www.dubaifaqs.com/wasta.php