It didn't. I complained on time and they let me keep my plan.

The prepaid plan has the following daily cost of data:

• 1st MiB free (oversight?)

• pay CZK 0.25 ($0.01) per every 256 kiB after that

• once you pay CZK 10 ($0.40) for 10 MiB, the next 90 MiB is free for the day

This is obviously a godsend to feature phone users, and every early mobile internet adopter would have taken this plan in 2003 when WAP websites were usually no more than 4 kB. A 1¢ or 2¢ overpayment if you somehow manage to go over is not too much, either.

The new plan:

• if you transfer any data, you pay CZK 12 ($0.50) straight away and can use 150 MiB that day

They touted it as an upgrade (150 MB/12 CZK is a better rate than 100/10) but it obviously isn’t, as many users will use less than the first MiB. But as opposed to in-your-face ads they ran for the original plan, this one was only mentioned in their monthly bulletin nobody subscribes to. To quote Hitchhiker’s Guide to the Galaxy:

“But Mr Dent, the plans have been available in the local planning office for the last nine months.”

“Oh yes, well as soon as I heard I went straight round to see them, yesterday afternoon. You hadn’t exactly gone out of your way to call attention to them, had you? I mean, like actually telling anybody or anything.”

“But the plans were on display …”

“On display? I eventually had to go down to the cellar to find them.”

“That’s the display department.”

“With a flashlight.”

“Ah, well the lights had probably gone.”

“So had the stairs.”

“But look, you found the notice didn’t you?”

“Yes,” said Arthur, “yes I did. It was on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard’.”

There was no “we'll upgrade your plan unless you opt out” prompt – people just started getting switched. I was lucky that my grandpa alerted me about his plan getting changed before mine was. I called the hotline and opted out just in time. The plan shows up as `` in my billing app but it still functions as normal. No new customers are admitted to the plan now so I really feel I dodged a bullet.

The service providers here cater to complaints so that they don't escalate into an anti-trust lawsuit that could break up their cartel. They will bill you obscenely but keep you “happy” with cheap gift giveaways, good customer service and excellent coverage. There is no option on the market for cheap data even if you're willing to give up some speed, reliability, free sunglasses or smiling customer reps.