Yes it's legit. Firstly you may doubt it because you never heard of it before but i have use it and it was good. I purchased data and i received it immediately.
Their customer Care is so friendly and active. Funding is so easy and the site doesn't lag.

It also has an app, you can install the app from the website.
How to install the app?
After visiting the website, scroll down to where you would see (get app on play store)
Click it to install app. So in conclusion, gablinks is a legit site to buy Data.