I am a subscriber to the Godata plan, which was due to expire on April 11. Recently, while abroad, my 1GB internet allowance was used up and so I had no alternative but to buy an extra 500MB, which expires on April 4.
I complained to GO that, whenever I use internet, the usage is taken from the data that expires on April 11 not from the data the expires on April 4.
I was told that Godata has priority over other internet usage. Which in effect means that the 500MB internet usage I bought (of which I still have 405MB) is useless and will expire with my not having used it. I think this is very unfair and the usage should be according to that which expires first.