"Fix" as in it no longer works at all? If that's the question, you can't fix it. Sandwiched inside inside there is a loop of metal that acts as an aerial, a tiny wireless transmitter/receiver chip and a small processor chip. You could have sat on the card and bent it, breaking the aerial loop. Been there, got that tee-shirt.
You need to go to a TfL ticket office to get it changed and have your credit moved to the new card number. There shouldn't be a charge as the card failed - unless the card looks like it has been deliberately damaged, such as having a big crease across the middle.
That is the correct spelling of the word "oyster".
Find a good gunsmith.
ask an at and t person
Brasil, USA, or Argentina
oyster
Try taking it to a att, verizon,t-mobile etc. store and see if they can give you a replacement
{| |- | O L in T |}
O t t o
n n n n n n n n n n n n n n n o o o o o o o o o o o o o t t t t t t t t t t t h h h h h h h h h h h h h h i i i i i i i i i i n n n n n n n n n n g g g g g g gg g g g g g g g gg gg g
t-o-m-a-t-o
a prepaid Sim card is a Sim card that you pay as you go AT&t tracfone and t-mobile
G O T O T H E D O C T O R O R T A L K T O S O M E O N E !