@Bapu Hey mate, first of all, you have to be running at least Mojave, secondly, it'll be in the app store. If not, speak to apple. When I moved from the US to UK again I had to get them to sort it out. One store initially tried to tell me I had to buy it again, I was like HELL NO!!. Anyway, if it's legit, which sounds like it is, it'll be there.
Tony