Why Is Orange PAYG Internet Allowance So Ridiculous?

I was on Orange PAYG, on the Dolphin animal setup. It said on the website I get 300 free texts and "free mobile Internet". Now tell me, if you read "FREE MOBILE INTERNET" you expect it to be unlimited, right? Apparently not, as I discovered after purchasing from Orange and topping up. It has given me just 100MB of Internet a month... I actually laughed when I read it. This amount will last me literally 4 days, which it did and if you go over then it charges extra. Just wondering if anyone else has the same problem, I am furious at the moment with Orange and I can't find a way to complain to them. I'd rather not ring them because I don't want to moan at somebody down the phone who's fault it isn't, plus they always try to be too friendly and never actually fix the problems. Is there any way of getting more Internet allowance too?