I luckily never encountered this problem myself, but I have heard from others that you can retrieve your account via the "Send Feedback" option (next to "FAQ", "Help Forum" etc.). If you message the FamilyEcho support with your problem and provide them with your former username/E-Mail (ideally both, I suppose) and infos about your family tree (i. e. name of the tree and names/life dates of a few people on the tree) they can restore your account.
For the future, maybe download backup your family trees as GEDCOM as well (not only PDF) - should something happen to FamilyEcho.com, you can upload and edit your tree to other genealogy websites (because I agree, remaking a larger family tree from PDF sounds exhausting).
I really hope this solution works for you - as I mentioned, I hadn't had to use it myself and only read in other answers that this way of retrieval was possible.
