If you’re from India, Sri Lanka, Bangladesh, Iran, Nepal, Togo, Nigeria or Uganda you cannot get an extension off a single entry tourist visa. I have no idea why. Indian nationals who come in visa exempt can get an extension. Go figure.
There are countries that won’t allow you to visit them if you have a stamp in your passport for another country (like Israel and Egypt) but they are few and far between.
Ah. So you didn’t get the METV at a consulate that is not your home country. Like every other human on the planet. You say that they said you could but you didn’t. Enough said.