Are you complaining that someone did not
tip you for something
LOL.
First of all, the both of you are almost certainly selling accounts that were ultimately either hacked or purchased with stolen credit cards (or will otherwise stop working in the near future).
Secondly, if he is selling at a higher price then it should put you at an advantage because your prices are more competitive. If a potential customer knows they are getting the same product from the same ultimate source, a free market will dictate that they will go to the cheaper source (assuming all else is equal)