Is Not Getting Renewed the Same as Getting Fired?

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The short answer is no. There are many reasons teachers don't get renewed ,such as . . .

• They want to clean house to avoid paying more into the pension.
• They can re-hire teachers and pay them less.
• They decide to have retroactive requirements. 
• You took maternity leave.

If you truly did something bad, a school wouldn't keep you on their staff and wait for your contract to run out. Don't take it personally. The bubble burst long ago and it's an employers' market.
Pick yourself, dust yourself, and move on. There are better jobs out there (the best TEFL jobs in the world is a good place to start looking) and you might as well get one of them.