Incorrect appearance of Sinhala font

There are two Sinhala letters that still appears incorrectly in Mac. I'm working with Pages and it is such a let down when I have to keep avoiding this letter. Its රැ and රෑ as in ratify and Rand (r+e) but always appear like ru and roo (r+q) which are different letters රු and රූ. The second part needs to be higher and at the top of the first part.

When I use it to post on the internet, PC's show this letter correctly in their screen, wish I could also see it correctly on my Mac screen.

I have installed a Sinhala keyboard for my iPhone and there it shows correctly.

Is there a way to correct this?

Thanks! Aruni