DPhil conditional offer GPA not satisfied

Hello,
I applied to Oxford for a DPhil and I got accepted. However, my acceptance offer is asking for a specific GPA for my undergraduate degree. The only issue is I graduated already and can't raise my GPA to that.
I'm now very anxious about sending in my transcript, as obviously I do not have that GPA. In fact, I did not have it upon applying, and I'll be sending in the exact same transcript I applied with.
Does anyone have any experience with this? my department is MSTP.