I was overcharged for the Tube

You probably forgot to tap out. If you forget to tap out you will be charged the maximum for your journey. You probably won’t be able to get a refund, because you are probably the cause of it, by not tapping out

Remember what you see on a credit card bill isn't individual journeys. It's a whole day's journeys. It's only charged once a day.

Transport for London Help & Contacts

Possibly you didn't tap out or didn't tap out with the same card or device.

I see from other your posts you are a group of 9. Did anyone use a card and phones tied to the same credit card?

If you were still in the UK you could create a TfL account and look at your journey history. That would tell you exactly what had happened. But you can't create or look at your account when overseas.
One of the reasons why I use an Oyster as the gates give me an instant warning if I do that from the balance displays. I can then go straight to a ticket machine and look at my journey history.
To get a refund you would need to know what had gone wrong.

You have 8 weeks from date of travel to claim a refund, which can only be done through your account.

Failing to tap in or out once also results in capping not being applied for the day as the system can't know what the appropriate one might be. This can all add up very quickly.

There are some other technical reasons why a journey can end up as a maximum fare in error. The main one relates to journeys finishing at one station and the next starting at another shortly afterwards, but they are out of station interchanges so the two journeys are treated as one which could be over maximum time.

You can open a TFL account from overseas but you must use a VPN that offers a UK IP address. (Not all VPN's are recognized.)

Did you travel only on one day or multiple?
There could be several reasons. Did you use the same card for all journeys and did you allow gates to close from the previous person before tapping out.
Did you present an individual card or tap on with your wallet containing other cards, causing "card clash"?

I used the same card the entire time. I tapped in and out, because, thanks to this group, I knew to do that. I think that perhaps the charges for 22.20 pounds may indeed be for two journeys on one day. Still, that seems quite expensive for a tube ride, all within the city centre. Next time, I will use an oyster card. Thanks for your replies.

Next time, I will use an oyster card.

Contactless credit card and Oyster card are charged at the same rates, no difference in price.

Did anyone use a card and phones tied to the same credit card?

My hunch is this may be the reason if one of your party used the same credit card account as you and TFL combined the charge into one billing. If you got separate Oyster cards for your traveling companions, could those charges coincide with that purchase?

No, I was absolutely the only one who used my card. No phones, nothing . My daughter realized that she got charged an exorbitant amount for one tube ride, and she actually found out by checking her bank online. She took that information to an agent at kings cross tube station who told her that it happens all the time , that people are charged more than they should be. You have to have lots of patience, online banking( which I do not), and download the tfl app, And you must remember the exact stations you used on the trips, in order to get a refund.

Were these charges on your credit card shown in GBP or USD?

Both, but I am quoting the GBP prices.