poor service, not adhering to agreement offer

i purchased a hp all in one machine and a free extended warranty plan was offered, the sales agent provided the necessary info to ensure the smooth sailing of the online free extension however, the website was closed, error, unavailable etc, the sales agent opted to contact head office, were it was continuous battle back and forth and thereafter advised cannot assist at all, i continued to call over period of three months to luck at all you just get pushed from pillar to post with the same people who refuse to assist. terrible service standards and very sad experience