So I jumped through the hoops to cancel Vivint at the end of my contract, sent the form letter in, and got confirmation that my letter was received. My end of contract date was the 12/27. Should I have been billed on 12/27 or is that Vivint hijinks?
We would not be able to speak to the billing practice/schedule of another service provider. If you do feel there is a discrepancy, you will want to contact that provider ASAP.
vivint is notorious for improper billing and for tricking people into verbal contract renewals over the phone a year prior to contract renewal date (most try to cancel only to discover when they continue to get billed, or go to collections that they inadvertently locked into another contract term).
You need to contact your financial institution and do an ACH revoke authorization