Did you do that with the RIO number ?
I mean, if you didn't put any RIO to switch the line to Sosh, it will be you to terminate your contract with Free.
Because with the RIO number it's the next ISP who will terminate your actual contract.
By the way, you can put the Livebox 4 in english.
All Free lines has been migrated to the new IPv6 DSLAM, you can see the old DSLAM (civ86-1) but with no customers on it :