There have been a few teething problems, and not all the Unlimited accounts got swopped over properly. Did you use the Unlimited25off40 code in the checkout? It only works if you got swopped over right, so don’t worry if it doesn’t.
Brenna has been helping people get their Unlimited status back, so you can email her at the community@lovehoney.co.uk address and she’ll hopefully look into it tomorrow. 
As for your order, a few people have had the same issue and have ended up paying postage/extra but once they’ve managed to get hold of Customer Care they’ve been given a partial refund to cover the excess. They are harder to get hold of now (I’m assuming a lot of other people are having issues too 
), but not impossible.
And if all else fails you can return the order for free and try again when the website is a bit more stable.