Salary revision or resignation

I was interviewed by Dell on 2nd August at Royal Orchid, Pune. I had cleared the HR round and was offered 35% on the previous CTC. However, there was some misinterpretation of my CTC on the part of HR because of which incorrect offer of 4.12 LPA was sent to me. My CTC was 3.88 LPA and I had been offered 4.12 LPA, which is 6% hike on my previous CTC. I had already provided my salary slip and then existing compensation letter. I had a mail conversation with HR and he had agreed that it was a mistake and he would be revising my offer to 5.25 LPA. I was waiting for the revised offer letter. Meanwhile, I had received joining forms from Dell. Again on contacting HR, I was told that I will get my revised offer letter soon and I should complete joining formalities till then. Based on this confirmation, I submitted resignation in Tech Mahindra and was serving notice period. I had chased HR for more than 3 months for the revised offer letter. I had sent him several mails to which he never replied. Also, he did not answer any of my calls even after several follow ups. When I tried to contact recruitment team on call, I was told that my revised offer is in approval process and will get the letter within 2 weeks. Again after chasing HR and recruitment team, they told me that I had to join on the package of 4.12 saying that they were not sure as to when the business approvals for my revised package would be in place. As I had almost completed my notice period in my previous company and did not have any other job, I was forced to join with 6% hike. Is this behavior correct on the part of Dell/HR/recruitment team? I am waiting for my salary to be revised as per what was agreed in the HR discussion and my experience. I have all the mails regarding this but Dell HR team is not ready to accept this and revise my salary. I have been sent out of India and have a 1 year bond - If employment with Dell end for any reason within 1 year of being sent onshore, I will repay all the costs paid to me or incurred on my behalf. Could you please let me know if there is any way that I can leave the company without paying any amount? Expecting a favorable action to be taken in this case.