Last month, I used my Oyster Card (twice) for the first time in at least five years. Since the balance was low and I don't have auto top-up, I did an online top-up before travelling, to collect as I tapped in for the journey. The money was taken from my credit card, but the top-up wasn't applied to my Oyster card when I tapped in
The money was refunded to my credit card several days later, but as a result I had literally pennies left on my Oyster balance. I repeated the whole process for the second journey a couple of weeks later, and again it didn't work. Money refunded fine, but now I have a negative Oyster balance.
Have I forgotten something very obvious about how online top-ups work? I vaguely recall in the past that I had to select a station for the top-up to be applied at, and the top-up only worked if you tapped in at that station. However, I wasn't asked to select a station when I made the payment online, and I can't see anything about a nominated station anywhere in the settings of my Oyster account, so at the time of making the payment I just assumed that this limitation had been removed in the years since I last used Oyster - but now I'm wondering if it's still there, and I just can't figure out how to see/change what my nominated station is.

Have I forgotten something very obvious about how online top-ups work? I vaguely recall in the past that I had to select a station for the top-up to be applied at, and the top-up only worked if you tapped in at that station. However, I wasn't asked to select a station when I made the payment online, and I can't see anything about a nominated station anywhere in the settings of my Oyster account, so at the time of making the payment I just assumed that this limitation had been removed in the years since I last used Oyster - but now I'm wondering if it's still there, and I just can't figure out how to see/change what my nominated station is.