Saying someone had struck you when he hadn't? (8,3)

'he hadn't?' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'saying someone had struck you' is the wordplay.
I cannot quite understand how this works, but
'someone' could be 'pi' (PI is an example) and 'pi' is located in the answer.
'you' could be 'u' (commonly used in online communication) and 'u' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

'when' is the link.

Can you help me to learn more?