I am an employee of Sprint and ran into the same issue awhile back, just vice versa. I was baffled at the beginning of the interaction, our customer had that number for several months prior and now it was a Verizon number. I contacted Verizon customer care with the customer in the store, this endless line of transfers lasted over 2 hours because nobody had dealt with this exact situation before and ended at the Verizon port department. I was assured it was a mistake on their part as an error in a port-in process and the problem would be fixed by close of business. I ended up contacting them multiple times over the next several days, in the end our customer decided to just change her number after having these issues for over a week.

I am not blaming Verizon for this issue either, I just wanted to give another side of the story. Something like this is very odd in our industry and there is no M&P for situations like this. It happens and we do our best to solve the issue with the information at hand.