Problems with prolong charger?

I bought the Prolong charger (only) on Oct 30, 2022. It arrived last Thursday, and I installed it the next afternoon, Friday. Unfortunately, the charger proved to be defective. The customer service guy suggested that I open the case and look for any obviously loose wires and/or just send it back. Not feeling comfortable with trying to fix a high voltage device, I got a return authorization the same day and delivered it to the post office before they closed on Friday. A new unit has been slow shipped and is scheduled to arrive on Saturday, November 12th. I’m disappointed by an apparently untested, defective unit being shipped to me in the first place, then having to wait a week for the replacement.

Anyone else have a similar experience with their equipment or was that just a fluke?

Thanks