BYOD was $150 per device so you're all set, never was $300 per.
Sometimes the rebate center is messed up, mine showed gift cards that I was never entitled to and they were cancelled out eventually.
BYOD = bring your own device, the wording confused me.
If the two new phones you purchased (and ported numbers to) were not an Apple or Samsung device, you received what you were owed at $150 per phone/line. If they were an Apple or Samsung device you woud be owed more. I suspect it's the former and that you received what was promised.