Burger King

So I ordered my usual, which is two Whoppers with no onions and extra mayonnaise with a large side of onion rings. This is at the Burger King at diversey and Cicero in Chicago.

There's a 21 digit survey code at the bottom of my receipt. The website only allows 20 digit codes. This makes it impossible to start the survey much less complete it.

Not sure what to do now or who to complain to, but the one time I actually wanted to fill out this survey for a free Whopper, I cannot. Absolutely terrible business practices. How can you have a 21 digit code on your receipt and your website only allows you to enter 20 digits? I cannot be the only one who has experienced this.