How much data have you used?
There are two places to look and they measure slightly different things. Knowing which to trust saves a lot of second-guessing halfway through a trip.
The figure that counts
Open My eSIMs in the app or in the Telegram bot and look at the profile for your trip. The amount shown there comes from the network that is actually serving you, which is the same figure the plan is billed against — so it is the one that decides when your data stops. Check it once every day or two rather than obsessively; it tells you whether you are on track long before you are in trouble.
Why your phone shows a different number
Your phone has its own counter, under Settings › Cellular or Settings › Network & internet › Mobile data. It is useful for seeing which app is eating your allowance, and it is not the number to plan around. It counts from whenever you last reset it, it can include traffic carried by your other SIM, and it measures at the handset rather than at the network. Treat it as a breakdown, not as a balance.
A lag is normal
Usage reaches us from the network operator in batches, not instantly, so the figure can trail real use by a short while — noticeably so if you have just watched something large. If the number looks stuck, give it a little time before assuming anything is wrong. It does not mean the data was not counted; it means the count has not arrived yet.
Running low mid-trip
Nothing dramatic happens when a plan is finished: the data stops, and that is all. Nothing renews and nothing extra is charged, because we hold no payment method on file. If you need more, buy another plan for the same destination — it arrives as a separate profile with its own QR code, which you install and then select for mobile data. Buy it while you still have a connection or Wi-Fi rather than after you have run out.
Slowing the burn
Two settings do most of the work: turn off automatic photo and video backup, or limit it to Wi-Fi, and stop video autoplaying in your social apps. After that, download offline maps for the city and any music or films you want on the road. Your phone’s own usage screen is the right tool here — it names the app that is spending the most, which is often not the one you would have guessed.