My actual boyfriend does not get to call me on my work line much less a guy that I don't know and have turned down. Repeatedly calling someone at their place of work for personal reasons, regardless of the reason, smacks of immaturity and a lack of boundaries. I would not tolerate it. Not to mention, you've already told him no. Unless it was a cutesy "oh, I couldn't possibly" since he's still calling your work, meaning you are probably sending mixed signals. So either you want to date him or you don't but want the attention since he's not doing it in a "stalking" way (your words). Either way, you've got to figure it out. Sounds messsssy messy messy.