Confused about unsuccessful uni applications, can anyone help?

I applied for 1st and 2nd year Psychology at Glasgow University, and have just recieved unsucessfuls for both. I don't understand why this has happened, as the entry requirements are AAAB, which is exactly what i have, including an A in psychology. I'm also sitting an HNC in Social Science this year, which if I got an A in, I presumed would let me into year two. I have been offered an unconditional for year two at Stirling University, which is of the same standard as Glasgow, which makes me yet more confused why Glasgow has rejected me without reason. Stirling is much too far away from where I live for it to be feesable that I go there, and Glasgow has always been my frist choice, so is it possible they have made a mistake telling me I've been unsuccessful, and is it possible I could still get in?