Yeah just to get the blu ray program to burn MP4s you need to download the whole package dvdfab13.
When you purchased it you had to have an email address.
Got https://www.dvdfab.cn/login.htm type in the email and password.
Check there to see if it shows the one program was purchased.
Then open dvdfab13 and authorize it with same email and password and it should change out of trial for what program you purchased to activated or lifetime.
If issues continue, in the member center is a why to create support ticket.
Depending on demand if can be 24 to 72 hours for a reply.
In this post is all ways to contact support,
https://forum.dvdfab.cn/d/472034-failed-to-connect-to-server-or-trouble-accessing-member-center-read-this
There is a possibility Mona will come along and can help better. She could check you account as is an Admin.