If I sold you a cue I wouldn't warranty the tip either.
I have absolutely no way of knowing what the buyer has done to the tip in terms of shaping and roughing. At the pool hall I constantly see guys abusing their tips, using a sander in an upward direction, stabbing and grinding their tip with tip-pik, or doing the "fire-starter," putting their tip into a glass encrusted square and rotating their cue back and forth between their palms and shredding the crap out of their tips. Not saying you are one of those guys but too many guys nowadays have no clue how to shape, maintain, and rough a tip.
Besides, tips are easy to replace. I think you need to suck this one up.