It's not the matter of contract le bro.... it's business ethics and care for loyal customers or existing customers...
They are not wrong... but I can't say they are not a DOUCHE or ASSHOLE about it....
You cannot compare subscription market to physical goods based market..... In subscription market, buyers don't come and go.... and the theory is to satisfy the customer cause it is 5x harder to get new customers than to retain old ones... from my experience in overseas... if customer's request is not unreasonable.. they will go way out to comply...

I am not asking them to give me 15GB package to match U-mobile also.... just to give me a reasonable quota for a reasonable price... is that so hard to do?? they give me their RM98 plan one also I happy liao... eventhough I am still paying more... at least I know they care... but if No changes... walao REALLY DOUBLE for NOTHING