When micro-SD cards are used with adapters, they are MOST unreliable. The micro-SD cards should only be used with devices that use them directly, without any adapter..
Micro-SD cards are not recommneded for use with Canon DSLRs. Look in your Instruction Manual for where it says what types of cards are recommended for use. Note the absence of micro-SD cards from being mentioned as one of the types of cards.
It sounds like the reader in the Internet cafe computers have corrupted your card.
You might be able to recover it by hitting the "low level" checkbox when you do a format (in your camera). I don't have a 750D but for most camera models it's the "trash can" icon button that toggles the "low level" checkbox (visible when you're on the format screen.)
I concur about the use of a card reader adapter. They're flakey ... hit & miss.
12/05/2023: New firmware updates are available.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.