Relaxation in notice period

I am working with an MNC for 3.7 years now. Recently i started looking for a job change and landed a great opportunity. The new organisation wanted me to join immediately and agreed to buyout my notice period. But my present employer wanted me to serve complete notice. So i had to let go of the offer, now almost a month after they have approached me again and are ready to give me another joining date which is just 3 days prior to my notice period ending date with my current employer and are saying that its one time, take it or leave it offer. But my present employer is not willing to even relax 3 days out of my notice period. I understand that according to the job letter we are supposed to be serving 30 days of notice period but not relaxing 3 days is literally sabotaging a persons career growth. This is something which is not in favour of employee at all. I cant see a clause for notice buyout in my offer letter, but I was able to spot this “ In absence of 30 days notice, the Company reserves the right to recover from me all expenses incurred, with regard to any training and development, special education, upskilling or on the job training imparted by the company or damages suffered by Company” Now previous to me, lot of people have resigned and they were given an easy way out through buyout, having same clause in their offer letters as well. I have tried every possible way to negotiate even i have more then 15 annual leaves left which could be adjusted but they are not willing to. Please advise what needs to be done as this is emotionally draining.