Some times it due to bad input on a computer address records or a mistake by a keyboard sales team member .
Often a company will buy a registered voters list to check or prove a customers address & risk assessment they also buy others it's a big business it only take a slip of a mouse and what has ben ordered 7 paid for gets sent to the wrong but correct address .
There are other explanations to do with fraud and being asked to pay such and such for it then being conned to give your bank details over when the seller says so sorry our mistake you far paid too much let me have your bank details & I'll refund you the difference . Then send you an email purporting to pay £2468 or similar to your bank . a few hours later you get another email saying help the new clerk and sent far to much but as it's innyour ccount they can't get it back would you refund us £2430 , keep the glasses and the extra money by way of us compensating you for our mistake .
If you pay thinking you've got some thing for nothing & have a fist full too boot .." Wrong ".you lose £2430 ..it's a suckers con.