Apparently a bit of mis-communication between the TDs and WFDF means that registration with the TDs starts in January but teams that have accepted their bids should pay WFDF _now_:

We informed you earlier that Registration should be open on 1 December. Unfortunately we have to move this date. WFDF wants teams that are eligible to participate at WUCC to pay $500 first to them and after team pays this fee (which is part of team fee) will be able to register with us. Their deadline for the first round of bids is 31 December. Therefore we are planning to open our registration process at the beginning of January. We are also waiting for some information from WFDF so there still might be some changes. The whole timeline of registration and deadlines will change and we hope it will be clear till the end of this year. So if your team has right to attend WUCC next year, plese pay first$500 to WFDF and as soon as we get approval from them that you paid, we will send you access to our registration system. As said before this should be happening from the beginning of January.