https://mfn20.myfootballnow.com/team/view/28
So I try renegotiating a contract with a smaller base but the negative number won't go below the amount that I am over the cap?

The contract bar won't decrease even if you offer a contract that would reduce it. The reason for this is that if you line up additional contracts with the assumption that your renegotiation will be accepted but it is not, your cap is in even more trouble than it was before.