I applied to geology course but i was offered geography, why?

Hi! I'm a girl from Finland and applied through extra to study geology in Kingston Uni. Instead of geology they offered me geography. Does anyone have an idea why this change has been made?
Of course i'm happy that I even received an offer, i had lost my hope a long, long time ago. I like geography but geology is the course i really would like to study... Do you know if it's possible to change it back to geology?
I would also like to hear some experiences about studying geology/geography in Kingston uni.
I sent an email to the university over a week ago about this situation but i haven't received any answer. Should i call directly to admissions office?