Science Lab Job

So i'm currently science chemistry/chemical engineering and recently met a guy who used to work as a manager but now is a senior lab technician at a chemistry company. i informed him that i'm looking for a job and experience and he told me that 'i can guarantee you a spot' in the chemistry side of the company. Anyways so i took his number and email sent him the resume and he said he would put in a word for me and hand it the HR manager who is a very good friend of his. Fast forward a week i am still waiting for a call from the company and nothing, i end up calling him on friday to see what's going on, he informed me the HR manager was away and (he forgot to tell me since he has two jobs i met him during his other job) said expect a call next week. So i decide to take matters into my hand the following week (tuesday) and call the company to speak with the HR manager, but i was sent to his voice mail so i left a message explaining the situation as well my contact info. it's Wednesday night an i haven't got a single call back from him, What do you guys recommend i do?? i really want to get this position as the distance is really close and the company deals with foods which i find interesting. Should i wait it out??? or give them a call tomorrow and see what's going on?? Also what baffles me is why would he tell me i can guarantee you a spot??

I have 2 more years left to get my bachelors, so i'm doing this for experience and it's been really hard trying to get a interview, talking at least 4 months of applying.