Two problems...1...you didn't say if you made a starter or not, I will assume not...2...I always leave my lagers at room temp until it becomes active then move it to the colder temps. Some people will pitch cold, but I don't.
I'd recommend bringing back up to room temp and rouse the yeast in there a bit to see if any activity starts. If not, pitch a starter. 16 days past expiration date is nothing. I've used yeast that was expired over a year. Just make a step up starter and it all works out.