Are you asking what additional facts, if present, could give rise to a legal basis to avoid the payment obligation? Or are you asking us to not go beyond the facts as described?

I would say the latter, since I'm not really looking for boring answers like "well, if the statute of limitations had passed..." or "the bank has frozen my funds" etc.

I replaced the word "bill" which has multiple legal meanings creating an ambiguity, with "invoice" which has a clear single meaning, for clarity in the title.

@ohwilleke: YMMV, but, in 2024, $15/MB meets the bar for "absurd" for me. I mean, we are not talking about satellite Internet in the Antarctic, we are talking about "you had a SIM card from the wrong carrier in your phone, so we charge you 1000x the regular price".

As someone has already said "The bill is correct per the contract" will for most jurisdictions end the story. Eg, many systems of consumer protection would make the relevant contract term void, but you have deliberately precluded that. An "if they had realized" argument will similarly be dealt with under contract law (cf law on reasonable notice and unreasonable terms) and you have again precluded them.

There is a company in the UK that sells low cost mobile connections to users with low usage. 1p per MB. And you pay £40 a year, and once that money is gone, it stops working.

@ohwilleke I think you're misled by OP quoting a price per MB. Usually, internet usage is billed per GB. A typical price where I live is e.g. 15 dollars for 60 GB of data. If I accidentally used the wrong SIM card for a month, this would result in a bill of one million dollars instead of 15 dollars. This clearly seems absurd to me.

@FrederikVds absolutely not in the UK. You will be billed per MB, although I've only seen it as high as £4/MB IIRC. The charge is literally obscene. This is out-of-contract usage such as going abroad and not having a "roaming" plan or just exceeding your monthly allowance in some cases (which, indeed, is measured in GB). It's a well-laid trap.

@FrederikVds a fun anecdote; about a decade ago I was in Dubai and the taxi driver got lost (not unusual back then as there is no proper address system, especially new developments). It cost me more for the single load of the map to get directions than it did for the taxi itself.

I can attest to what @roganjosh says, I've seen data billed by the MB here too

@roganjosh My point is basically as you say, they will quote prices per GB in any price featured in e.g. advertisements. They only switch to quoting prices per MB in specific situations, to hide the fact that they're increasing prices by a factor of a few thousand.

@user541686 You referenced me by mistake, should've been Francis Davey.

@FrederikVds: Oops yes, let me repost my comment, sorry/thanks!

@FrancisDavey: where did I deliberately exclude contract law for an "if they had realized" argument? I certainly didn't intend to. (If I had realized... I wouldn't have...)

@Heinzi it can be even worse: "you had our SIM card, but registered in another region, so we'll overcharge you anyway" - for example T-Mobile, with overpriced roaming despite the carrier's worldwide presence.

In the first years of smartphones, in the Netherlands, prices were about 3€/MB if you didn't have a data plan. At the same time, carriers were so desperate to get people to actually use their recently rolled out 3G networks, that you could get an unlimited data plan for 3.75€/month. I had a 'fun' experience where I went to my carrier's brick-and-mortar store to get a data plan, but the clerk failed to press the submit button or something, and a month later I was presented with a bill of 1500 €.

@ohwilleke for reference, a couple of days ago I read about a US tourist that received a ~140K (yes 140K not a typo) phone bill after a holiday in Switzerland. He apparently managed to have it waived but I think it proves that costs can indeed get absurd in certain cases

The effect of a lot of protections against unreasonable terms in many jurisdictions is to invalidate a term or terms of the contract, but when you say "the bill is correct..." it seems to imply that the contract is valid in the first place. Perhaps you could clarify what you mean by that.

To be clear it is the "technically correct" part of this that is causing a puzzle. I suspect what you mean is that the bill is not technically correct, but that the literal wording of the contract document has been complied with or something like that.

@TrangOul some instances of the T-Mobile/Telekom brand are not operated by the same entity anymore.