I recently fell foul of maritime data charges. Ok, I should have been smarter and switched off my data roaming before the ferry sailed out of BT mobile range.
My gripe with BT is that three different sources were used to send me messages about my data usage.
The first message informing me that I was using "maritime data" was from "BT mobile".
The second message informing me that I was nearing my pre-set (luckily low) data costs limit came from, "BT"
I turned data roaming off. Sometime later I got a message simply showing a phone number, no mention of BT, now telling me I was "using data in France". I wasn't.
Why three sources?
I initially thought the last one could have been some sort of scam.