Alphauserpoints sync issue

I run Joomla! 2.5.11 and just installed the latest AlphaUserPoints component (version 1.8.3). Before I can use it it asks me to sync my users. However, the sync process seems to freeze every time and I do not see any table updates. I have almost 15k members on my site and don;t know if that is the reason. On another site which I just launched (30 members) the sync process went without any issues. I need somebody who can fix the "sync" problem. I prefer a person who does NOT need to access the server and can give me instructions what to do. Maybe of importance: in the configuration (under "integration" tab) I see some Uddeim settings. I do not have Uddeim and no intention to install. However I see a very long list of ALL my users there (takes forever to load that config tab) and the users are shows SEVEN times!. There must be some bug which might be related to my sync issue.