Ranking up players - HELP.

So, yeah, ranking up players - I've got that down easily, so long as it's done manually.

What i would like is a system to do it automatcally when they fulfill a certain set of requirements.

For example, Francis is rank 1, to ascend to Rank 2, he needs 40 sponge and 10000 iconomy money.

Using MyCommand I can automate the execution of a command to deduct the items, and the '/money take Francis 10000' command.

But that raises the problem of people just obtaining the 40 sponge, then performing the actions needed to rank up, then when the commands are executed, it would put them into a negative balance.

What i need is something able to deduct the money from the player ONLY if they have enough, and deduct the items from the player so long as they have enough.

Obviously this is easily achieved manually, but this causes a lot of work for our admins, so a technique to automate is ideal for us.

Thanks.