Academic Reference EdD

I have accepted a conditional offer at a university to study the doctorate in education.

I have already provided 2 references but the conditional offer is to provide another academic reference for academic suitability.

My academic reference is the lead of my last post grad course but they didn’t mark my work so it is not appropriate for them to comment on suitability.

My main tutor said they would do the academic reference but it has been 3 weeks and they have not. I’ve reached out to them yesterday but did not hear back.

My other post graduate course before my last one was 5 years ago so I do not have their details anymore.

What do I do? Will I ultimately lose my place now as I am struggling to find another academic reference?