Person with a UK email but Wisconsin phone number wants to sent me a cheque for something I posted on kijiji. Seems a little odd. Anyone else?

Somebody from this number once they give us a check for more than the item you're selling and then wants us to send them a check back seems odd doesn't it.

Its way beyond odd.  Its fraud.  And its old as dirt.

The way the scam works, the buyer gives you a paper check that you are to deposit in your account.  You are to wire part of that money to a shipper selected by the buyer.  Your wired money transfer clears instantly.  The buyer's check bounces, but it may take 2 weeks or more.  You owe your bank the full amount of the paper check, including the shipping fee you have already sent to someone else.  You also owe your bank a fee for depositing a bad check and you may be in trouble with the law for passing a bad check.