I would contact GOG and see what is going on. Since it's Friday, it will probably be Monday before you hear back, but they've always been very good at answering my questions promptly. The new download manager seems to be working very well. I just did a 15 GB download of Witcher 2 that took almost a week and it let me pause and resume numerous times.
In my PC corner for the winter, gaming, knitting and reading.