Sounds like by "after deciding not to purchase" you may have attempted to cancel escrow based on whatever provision of the purchase and sales contract, assuming there was one. And also depending on basis you used to cancel, again based on the underlying contract, you may or may not be entitled to receive your deposit. ( not clear from facts).
Your tenancy and it's termination usually not linked to the purchase and sales contract.
You should hire and consult with a real estate attorney in your area to review the purchase and sales contract for various provisions and conditions and write a demand letter on your behalf for the return of your deposit.
Good luck to you.
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