Xieguyoi20
No problem between Paris and Basel, this is the same train and your ticket is still valid.
In such situation tickets are also valid for the next connections. You don’t need to buy any other tickets. The problem is that you no longer have seat reservations from Basel or Zurich to Como.
I see two solutions:
If you bought the tickets through SBB, you could call the SBB Contact Center with this number to make an exchange (free of charge):
+41 51 225 78 56 (24/7, waiting times may occur).
Or you could ask the Swiss train staff in the TGV between Paris and Basel to ensure that your ticket will be valid to Como in another train, but it would no longer be possible to get new seat reservations.
You can later also obtain a compensation if you arrive in Como one hour late.