Hi Adam,
Thank you for the feedback.
We have certainly not had any issues with the Removal Boxes Strength to date.
They may look very similar, however it's likely that once the thinner boxes are full and stacked on top of each other they will crumple and fail. Having an extra 1.5mm and Double Walled will make a difference i'm sure.
We are sorry you experienced issues with the Courier & Delivery. Unfortunately this is very much out of our control, however we do our best to help in the event of any rare issues with items being delivered.
Kind Regards,