Anytime you say "something is yours to lose" it means that your future actions, or lack of action, will determine if you get or retain that something. What other people do or do not do will be far less important than what you do. So, in this case, the ability to get the job is totally within your control. Score - in this context, score means to get, attain or win. Think of scoring a goal in football or hockey, scoring a run in baseball, etc. So, in this context they are saying "get the job of your dreams".

This sounds like a scam to me, if it looks too good to be true, then it is.