Unjustified Delay in Returning Security Deposit by Landlord

I vacated a rental property on April 1st, leaving it in perfect condition. Since then, I have repeatedly asked the landlord to return the security deposit, but he ignored all my messages.

When I finally reached him by phone, he promised to return the deposit within a few days. It has now been a week since that call, and after I followed up again, he responded saying he would return it by the end of May.

I'm not sure if the Ottawa Police will take any action in this matter.