jonb: kudos to Vodafone on this issue at least, my usage count seem reset at 12pm exactly at the end of the monthly cycle. And have used a few GB over the allowance with no penalty the following month.
heavenlywild: So currently the best solution is to use your remaining monthly data at least an hour or two before midnight.
anatoki: While I see it's frustrating that you may end up paying for data you don't use, it's a matter of a few dollars here and there, no?
It's no different to the way that Vodafone bill on account customers who have remaining minutes on their plan at the end of their billing cycle. Do you think everyone rushes around making phone calls to use up their last remaining minutes? I don't.
The only company out that that I can think of that would suit you Screeb, would be Xnet who are Pay-Per-Meg. At least then you're only arguing with them over rounding up to the nearest megabyte ;)