Hey guys, a little advice needed!!

I sent a message to the sister of a girl i was sleeping with a little while ago, asking for the girls number as i'd genuinely lost it...after she sent me the number, i replied back saying "cheers fuckface" - as i normally completely bust her balls in a similar fashion when i see her/and it is tongue in cheek, she knows its playful. However, this seemed to have triggered a bad response this time along the lines of 'my sister deserved better than you, i actually hate you, etc.'

I'm thinking is she attracted to my cockiness and dealing with it by kicking off at me?! Or does she genuinely hate it!! Tough one.

Do i come clean and tell her its just a cocky front i put on and im not that bad really, or do i continue with it, and reply to that message with say a *wink* or something as cheeky, maybe just 'respect'?!! Or do i red flag this situation and leave her to it without a response at all. I like a challenge though...and she is an 8.5