Employement Bond of PSU, valid or not?

Sir/ Ma’am I have a query regarding employement bond. I was hired by a PSU, in offer letter i was asked to sign an employement bond of 10,00,000/- for a period of 7 years. It was mentioned in the letter that on joining i will be provided training for 12 months approximately, and on completetion of the training my 7 years of bond will start. During my training period i was given a stipend of 10,000/- per month. Since my traning stretched to 3 years due to companies administrative reasons, will the bond start from the day i finished the training? ( since it was not my fault that training stretched to 3 years, can I negotiate on this) Secondly- During my traning days, due to financial condition of the company, i was not paid stipend for 3 months as well. This was later paid in installments along with the Month’s salary over a period of 3 years. ( one old stipend payment every 6 months or so) I wanted to know what would be the implications if i decide to leave the company after 5 years from completion of the training. ( total 3+5. = 8 yrs) If company goes to court to get the bond amount, what are my options. Your help is appreciated. Thank you Regards Sagar