I ordered and paid for a kit direct from Modelsmaster, using PayPal, around the same time and received it around 5th January. It was apparently dispatched on 21 Dec but with the normal Christmas postal chaos, and the fact that it was coming from Spain, it took some time.
I was also concerned about mine and emailed the company a few days before it arrived. My experience was very good - they came back to me very quickly with a reply and a tracking number. The tracking number was partially helpful, in that I could find out it had arrived in the UK several days earlier, but no info beyond that. It took about another week to get to me, but I guess this was due to the combination of Correos and Royal Mail, rather than Modelsmaster.
I think I emailed them via their website.
Hope you get it sorted.
Don
P.S. When it arrives, perhaps we can consult about where some of the bits are meant to go - I'm slightly confused