That’s really frustrating when you thought you had an arrangement in place. A few things could have happened here.
Most commonly: payment arrangements have very specific deadlines, and if you missed even one of those dates by a day or two, the whole arrangement can void and your account goes back to “past due” status immediately. The system isn’t forgiving about it.
Based on what you described - paying on the 2nd instead of the 1st - that one day difference likely voided your arrangement. It seems harsh, but their automated systems don’t have much flexibility built in.
Here’s what I’d do: call Spectrum right now at (833) 267-6094 and ask to speak with someone in billing. Have them pull up the payment arrangement details - the exact dates and amounts that were agreed to. Explain that you paid one day late because that’s when your income arrived.
If you held up your end mostly correctly, push back and ask them to reinstate your service and set up a new arrangement. They’ll usually do this once, especially if you can make a partial payment on the call. For future arrangements, always ask if they can set the payment date a day or two after your payday to build in a buffer.