How to get reference from my college for security pass at my new job?

So I have just got a job at an airport, I already work at said airport as a bartender. I will be transferring to be a ramp agent (my degree plus a few years experience in the related field should hopefully be enough to set myself up with a nice career in the aviation industry). For the new job I will need to apply for a new airside security pass (this is normal) as part of the vetting process they require a 5 year education and/or employment history with any gaps over 28 days being accounted for. The issue is the last time I tried to get a reference from my college, I simply asked my lecturer and she gave me a reference, confirming that I was studying there when contacted by the company etc etc. However, this time she is not answering my emails so I am assuming she no longer works there. I have no idea what department to refer to when it comes to situations like this. Any help would be greatly appreciated!

So I have just got a job at an airport, I already work at said airport as a bartender. I will be transferring to be a ramp agent (my degree plus a few years experience in the related field should hopefully be enough to set myself up with a nice career in the aviation industry). For the new job I will need to apply for a new airside security pass (this is normal) as part of the vetting process they require a 5 year education and/or employment history with any gaps over 28 days being accounted for. The issue is the last time I tried to get a reference from my college, I simply asked my lecturer and she gave me a reference, confirming that I was studying there when contacted by the company etc etc. However, this time she is not answering my emails so I am assuming she no longer works there. I have no idea what department to refer to when it comes to situations like this. Any help would be greatly appreciated!