Senior Maths Challenge missing certificate?

Hi,
Earlier this academic year in October I took part in the Senior Maths Challenge and was told I would receive a participation certificate, but have not received anything yet. Is this a normal wait time or do I need to contact my college about it? I am currently writing my UCAS personal statement for a maths degree, and am hesitant to mention the maths challenge knowing I don't have proof that I did it.

Did you get gold, silver or bronze? Participation isn't worth mentioning

I don't think so, but I don't have any other extracurricular maths experience beside reading books about maths, and I'm not applying to Russel Groups or anything. Would it still not be worth mentioning? It shows my enthusiasm for the subject