My sunglasses lenses are cracked. what is the best thing i could do to fix them?

[Bantry]

i was thinking about using fire to melt it a bit and see if they reform? xD but i have no idea if that's a smart thing to do. and, i saw some websites that could replace lenses, but i don't know how well i can trust them. any advice, inputs anything would be helpful. thaaanks!

[Bar Harbor]

use fire ? OMG ,you scared me .stop doing such stupid thing ,or you will damage your glasses entirely .just take them to the place where you bought them and ask if they could do it for you .