The notice period beyond 3 months is unreasonable. The contents of the bond posted by you are surprising and one shall wonder such kind of bonds can also be drafted. It is important that you reply to the notice. You may consult elders in the family,competent and experienced people known to the family, lawyer/law firm having experience and competence in handling such matters, and submit a terse and strong reply. The sane person who has crafted the bond , in all of his wisdom and sanity may be thinking of filing a recovery suite. In future kindly consult elders in the family,competent and experienced people known to the family, lawyer/law firm, before signing on the dotted line. It is better than repenting later.
Your are not required to pay anything as their wish. Just reply if they served you notice stating that the bond is not valid because it is one sided and you were forced to sign the document since they were making use of the situation and it is time barred as well.