There are no bonus boxes in the offers.
The Flawless Box costs 390 gems, discounted 315 gems, and contains HL engines or gems.
In Special Offer til tomorrow and in the Vintage Offer til Sunday are/were Bonus Local Slots for
350 gems, discounted 280 gems.
If you bought one of these slots your number of local slots in the Train manager should have been increased by 1.
Otherwise you have to contact support.