>>507475860 (OP)If you entered the country with a Greek passport then the people you owe will likely sell your debt to a Greece-based collection agency. Since the amount is high enough to be worth chasing, there's reasonable chance they'll bring it to court and actually shake you down for it by garnishing wages or seizing assets.
Because you're in the EU the process is easier for collectors than if you lived in somewhere less connected. Of course there's a chance your file will get lost somewhere in bureaucratic inertia or that it won't make it to a local collector.
If you're a Canadian citizen and you've fled to Greece you'll still be expected to file your taxes, which will allow the government to find you. If you don't file your taxes you may find that your consular protections will be revoked, meaning you'll have no legal protection in Greece and you'll be detained by immigration authorities and deported back to Canada if you try to use your passport at an airport.
If you're in a debt too deep to dig yourself out of there's always the legal process of filing bankruptcy, which exists specifically so that ordinary people have a way out of crippling debt without just running away to Thailand or living as an outlaw.