Update - I instructed IB to lapse the options, but they still exercised them! No big deal - sold the shares for $100 profit. Here's the interesting - I couldn't open the position because of margin requirements in Canda, but since it was exercised, I had the maintenance margin, so it didn't liquidate. Still - why didn't lapse options work - triggered it on Friday.
The cut off time for notification for equity options is 4:30 PM EST. I would guess that you did not notify IB before that time.
Which position are you referring to? If you had the margin to cover $26,600 worth of SPY why did IB contact you in the first place?
I didn't have the margin to enter the position and it was unclear what would happen under an option exercise scenario without that. Maintenance margin is lower than initial margin.