We last visited London 2 years ago and saved our Oyster cards which we had to keep as they no longer have refunds for them, we then took them to London again last week to use them only to find they had been blocked from being useable and we could no longer return them for our original deposit either so had to buy another two Oyster cards, we tried calling the number on them as we were told and could not even get through to a human to unblock them, absolutely useless service and pointless system for those who are only visiting London for a short period.
