a friend of mine pointed this to me, some part of the Law that i and a lot of other people weren't aware of. 12. SERVICE COURT ERRORS 12.1 A service court error has been made when a player: 12.1.1 has served out of turn; 12.1.2 has served from the wrong service court; or 12.1.3 standing in the wrong service court, was prepared to receive the service and it has been delivered. 12.2 If a service court error is discovered after the next service has been delivered, the error shall not be corrected. 12.3 If a service court error is discovered before the next service is delivered: 12.3.1 if both sides commiteed an error, it shall be a 'let' 12.3.2 if one side committed the error and won the rally, it shall be a 'let' 12.3.3 if one side committed the error and lost the rally, the error shall not be corrected 12.4 If there is a 'let' because of a service court error, the rally is replayed with the error corrected. 12.5 If a service court error is not to be corrected, play in that game shall proceed without changing the players' new service courts (nor, when relevant, the new order of serving).