A stable internet connection is a requirement for the game. If you are having internet issues, you should consider refraining from pvp or team based activities. When you leave, regardless of if due to internet or quiting you are having a negative impact on other players who also paid the for the game. However, if you would like to pursue a refund, you would need to speak to the retailer from which you purchased the game and would need to be within their refund policies.