I booked a room in July 2019 and made the payment online through a booking platform. On the day of the booking, the owner called me and informed me that the place was fully booked and they couldn't accommodate me.

This itself was a major setback as I was informed ONLY ON THAT DAY. I asked them to refund the money back to me, to which they said they would.

It's been over 3 months now and I still have to call and check once in a whole on the status of it. They keep giving me false promises to transfer it back but there has not been any update since.

I contacted the booking platform and they tried to get it done from their end as well but this place keeps ignoring them in the same way.

They are a bunch of cheats who even after making a mistake did not want to do anything to make it right. You'll be much better off finding another place as the location and colombo itself has a plethora of other options which would be much better than going through this headache of a "business".