If you suffered from untimely disconnection when switching your line from Free to VDSL and you already benefited from the last update deployed yesterday (3.1.2), perhaps you should give the operator a chance.
The update is thus particularly interested in the resolution of bug # 16403 which intervened in certain users when they tried to take advantage of the advantages of VDSL2. On the menu of disappointments: poor management of flow adjustment and loss of synchronization in mess.
Since then, subscribers suffering the most from these desynchronizations were advised to switch their lines back to ADSL 2+ technology in their user interface.
But since Free has probably solved the problem, everyone is invited to test again the switch to VDSL2 in order to benefit (depending on the case) from a marked improvement in incoming and outgoing speeds.
To do this, go to your Freebox subscriber interface, then in the freebox section: synchronization management in VDSL2 to restart automatic selection. The taking into account of the modifications occurs only once every 24 hours, you will only have to wait to note the changes.
Note that depending on the quality and length of the lines, disturbances may remain, it is then necessary to make a similar adjustment to force the switch back to ADSL 2+ again.