@ da_ru: you can check the status of your visa at the MOI site: http://www.moi.gov.qa/VsaWeb/Actions?action=getVisaInfoInput&language=En...

My understanding regarding visas is limited and using that site, the only information that I see are details of my passport, and these words below: Visa Expired, Transferred to Resident

I called my previous employer and this is what they told me, the system was supposed to automatically cancel my visa 6 months after my departure. They're checking my problem with the immigration. I guess the last recourse is to get an NOC from them. Thanks anyway.