(Hi everyone, I'm new to the board).
I found this contact information for getting replacement threads for dimensions kits:
"f you are short of threads, or other parts of a Dimensions Crafts kit, you should contact Dimensions Crafts customer service on wiltonindustriesinfo@wilton.com. Please remember to give your full name and address.
For a conversion table of Dimensions Crafts thread colours to DMC and Anchor Click Here (.pdf) or Here (.xls) "
Hope this helps!