Missing alphabet

I hate people who say they are busy after attending their phone calls. I think you should not be answering if you don't have the time for the caller.
But then, I did exactly the same in a crucial situation last week.
After five minutes I received a text message. "Having 10 passes for the tennis tournament as if your friends are interested."
Reading this, I concluded that she is angry with me. I called her and arranged for meeting up the next day.
Amidst our chit-chat, she asked whether I had enquired with my friends about going to watch the match. I started apologising to her complaining about the hectic routines. She was wonder-struck by my reaction. Explaining the situation, I showed her the message and she burst out laughing.
"It is a matter of 'K'."
I was sure that I've made a fool of myself but didn't have a clue. She re-read the message for me. "Having ten passes for the tennis tournament ask if your friends are interested."
I had no words.