[Solved] How come :SetAsync and :UpdateAsync do not work?

I'm making a custom chat system, and whenever I try to chat, it keeps spamming my chat with "Unable to cast value to function". Here is my code.

local chat = game:GetService('DataStoreService'):GetDataStore('GlobalChat')

local function UpdateChat()
    chat:SetAsync(5, chat:GetAsync(4))
    chat:SetAsync(4, chat:GetAsync(3))
    chat:SetAsync(2, chat:GetAsync(1))
    if plr.Name == 'hiimgoodpack' then
        print('Attempt to cast '..Filter(msg, plr))
        chat:SetAsync(1, tostring('[Owner]'..plr.Name..':'..tostring(Filter(msg, plr)))) --Whoops, forgot to add a return to the Filter function.
    else
        print('Attempt to cast '..Filter(msg, plr))                                         
                chat:SetAsync(1, tostring(plr.Name..':'..tostring(Filter(msg, plr))))
    end
end

local success = false
repeat
    wait()
    local s, m = pcall(UpdateChat)
    if s then
        success = true
    else
        warn('Could not update chat due to '..m)
    end
until success

Whenever I type something, it always says "Could not update chat due to Unable to cast value to function". Also, I tried :UpdateAsync and it had the same problem. I also tried doing it without a pcall, and it still errored. Also, if you guys could explain to me, what is the difference from :SetAsync and :UpdateAsync?