Or you could also chase that person again- you’re bot being annoying, job is more important than a feeling
I would be upfront with them honesty will get you further and they will respect it more just let them know you don’t have a reference letter to give explain why then ask if you could provide a personal reference instead could be someone you worked with before, a husband, Bestfriend, anyone.
Just explain you are still waiting or perhaps just pass their details on to the employer and they can contact them