Hi Vercinwil. There is not a way for you to view messages for other lines on your account without having access to the device itself. However, if you want to shoot us a PM, we can access your account and take a look at the messaging history. We won't be able to see the messages themselves, we can provide some basic details about messaging on your lines.
If you had received these messages on your iPhone, the dr.fone for iOS can help you retrieve the lost text messages from iPhone. Watch this: youtu.be/BOZOMqgSKhc