I think the minimum is 3 weeks salary per year pro rata.
That is 7 weeks gratuity. Leave is also defined as a minimum, but depends on what your contract says.
However the guys you are dealing with have only one goal in mind, saving one riyal for the company justifies their existence! They will try to use any trick to fool you, what else can they boast about when they get together. Go straight to the labour department for an opinion on what is due to you, this will take a little time but you will gain money almost certainly.