How to make a backpack stop getting filled up when you max it out?

Hello,

Hey I need help I am making a simulator and I need a backpack to stop when the script reaches 25! I already tried this and it did not work.

(btw lots of the stuff are variables in the script) (Stats is the Cash in leaderstats)

game.Workspace.sell.Part.Touched:Connect(function()

stats.Value = 25

end

And it did not work! Please help me.