Try this
https://www.bitrefill.com/ they accept bitcoin deposits and you can top up any mobile around the world.
There rate is also quite cheap compared to what others have.
do you gurantee of its legacy? and also have you tried it before? also how much time it takes to complete the process?
I had tried them before and yes they are legit , you will get instant topup after 1 confirmation, you can also try piiko.co , they also accept bitcoin.