Received a penalty fare for someone that doesn't live at my address.

t0rt0ise

Andy_L said:

reseal it, write "not known at this address" on it & stick it in a post box

And add "opened in error" if it looks messy.

martindow

OP, have you spoken to your son about this?  As suggested above, I suspect he or one of his friends could well know something to explain how this letter has come about.

rollingmoon

Your credit score is a made up magic number that matters to no-one. Write back to them, offering no other information than no-one of that name lives at your address.