Better Clearing Choice

Hi.

So I may have been to hasty with some things.

I rung CU scarborough because they still hadn't replied to my application earlier, and they put me through to clearing. Clearing offered me a course choice which was better than one I previously chose: 3 year BSc in Comp Science instead of 1 year HNC.

When I went to check if I could apply for clearing on UCAS, I noticed that my original application for the HNC had been accepted and changed to an unconditional confirmed offer (I can see by the course code it's the HNC). Should I ring up and ask to be released or is it to late, or can I just do the HNC then move up to the BSc after a year?

To add to this, I've already changed my finance application to the BSc course instead of the HNC, will this matter?

I'm so confused! Help!