The Valeant vesting policy on the B+L matching is:
For the 7.5 % matching – 33% after 1 year, 66% after 2 years and 100% after 3 years.
For the 2.5% matching – 0% until 3 years when it becomes 100%.
Did it previously show 100% vesting when it was the B+L 401(k)?
If it previously showed 100% before the switch then hopefully you have proof (screen shot, printout) and you should contact HR, I would think you should get it back.
Also if it previously showed 100% before the switch then it sounds you should have rolled that over into an IRA before Valeant had a chance to mess with it.