Datastorage issues and nil values?

ok i cant find any help still and this is making me go mad, sorry for posting the same script, its b a different issue im relatively new to scripting and was given a short weekend of training from a realllllyyy good scripting friend (hes never online and he doesnt know much about datastorage), and im trying to use datastorage to save stuff via google docs, it doesnt seem to work still and ive done everything right, everything is in the right place and whatever

the issue is that the script cant find the "money" value

heres the script my lovelies:

local ReplicatedStorage = game:GetService("ReplicatedStorage")
saveMoneyEvent = game.ReplicatedStorage.saveMoneyEvent
httpService = game:GetService("HttpService")

local function onSaveMoneyFired(player,money)
print ("it has arrived!")
player:WaitForChild("cash").Value = money --- issue
local databaseService = require(game.ServerScriptService.DatabaseService)
local globalDatabase = databaseService:GetDatabase("Global")
globalDatabase:PostAsync(player.Name,money) --- issue aswell from the money 
print(money) --- issue aswell from the money
end

saveMoneyEvent.OnServerEvent:Connect(onSaveMoneyFired)

it said it was a nil value, but it doesnt say any errors anymore and idk what ive done