Being connected to your neighbours line is usually a temporary measure whilst VM sort out cables to your property... it shouldn’t make any difference to the overall performance of your connection though and doesn’t change the service you receive in any way...
The issues you are having could happen irrespective of how your home is connected, we’ll need some more detail to help diagnose what the issue is..
VM staff here seem to be a little more capable of engaging the correct internal departments than the staff on the phone, so if you hang around for a few days someone from VM will eventually respond...
in the meantime, can you set up a BQM - once set up, find the Live Graph and click "Create Sharing Link" - post that back here.
Next, browse to your hub on http://192.168.0.1 - don't log in, click Router Status - copy/paste the tables from the Upstream, Downstream and Network Log tabs back to this thread - you'll need multiple posts for this, the info wont all fit into a single one