Hello @JanM06 ,
I'm only seeing a few brand new additions to your contacts from yesterday, and your activity is only otherwise showing list deletions. How were you adding these contacts? Were you doing them one-by-one, adding them via the type/paste multiple method, or were you uploading them via file?
There's a myriad of things that could potentially interrupt your internet connection and/or connectivity to our site, which could result in lost efforts when trying to use the type / paste multiple method for a very large number of contacts. For a large numbers of contacts, it's generally better to use the upload via file method so you can be regularly saving them directly on your device as you're getting them compiled. Then you can just upload them all into your CTCT account in one go.