ASUS TF700T - pathetic service - aftersales support

tf700t was bought through amazon by me and to my surprise it stopped functioning in just 45 days all of a sudden and i gave it to asus for repair on dec 10 2012.till today jan 21 2013 asus has not told me what is the problem with the tab or what they have planned to do for me.they keep changing their stands like intially they promised to change the mother board and return the tab.later they told that they will replace mine with new tab.then the latest promise is that they will provide me with a credit note.but when i e mail asus asking for more details nobody even replies to the e mail.neither my tab was replaced,nor credit note was sent by them.i am reaching the limits of my patience and am thinking of filing a lawsuit.
poor service by asus did not expect this from them i should have gone for samsung as most of my friends recommended...i beleived in asus and they have taught me a good lesson