See if I'm reading this correctly - this is a co-worker but not someone you report to or that you even work in the same department. You don't normally interface with her at your job. You both just work at the same company?
If that is correct, then either she has taken it on to make trouble for you (she sees you as the weak animal about to be eaten - she's a preditor) OR the higher ups have told her to make you look incompetent even though what she is accusing you of is not your job.
If this is correct, then you need to email all involved, including HR & set them straight - nicely.
From what I remember SF used to be the second biggest city for ad agencies? Please get your resume together. I know several people that left ad agencies & now work in a large companies marketing departments. They love the work & the enviroment much more than the dog eat dog of an ad agency.
