The ultimate problem here is that there is no collection of the names or totals. All you have is the last item in the list.
The constructor for creating the totals is mostly correct, you do need to chomp off the trailing linefeeds from the scanner though. When you do non-string > non-string, etc, then try to retrieve string, the results is that of the linefeeds left by the scanner when fetching the numbers. A simple call to nextLine() after you are complete with the numbers removes that excess line feed.
Personally, I'd write a new class to contain each seller and their totals. Then all you need is a collection of that type, and you can draw the totals (either statically from that new class summing up a collection, or from the reporting class which iterates the existing ones). Then its easy to construct too, with something like this:
public SalesReport(Scanner in)
while (in != null && in.hasNext())
this.sellersCollection.add(new SellerInformation(in.nextLine(), in.nextDouble(), in.nextDouble());
The other pro to this is you can now use a Comparator to sort the sellersCollection.