Hi,
I assume that you just purchased the car only a few days ago, re: canceling the check. I would go ahead and do this asap, and demand the dealer supply you with the second key. For a 2006 Toyota, they should have definitely given you two sets of keys. Most likely they lost one set or only received one set. Demand they supply you with a second key, preferably two additional since you lost the first. Dont release the check until they do this. They will.
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Auto locksmith Dallas