This month, I got a job offer and the company asked me if I could render a 30-day notice instead so I could start with them asap.
I sent my resignation letter to my boss three weeks ago with a 30-day notice. He has acknowledged it on the same week, we talked about it the following week, and he even said that it was indeed a good offer. He never raised any issue about the 30-day notice.
However, this week, they insist that I give a 60-day notice instead, and implies that I will have problem with my clearance otherwise. What should I do with the implied threat?