Ceiling A/C vents will not turn or open

[TFH]

Isata3
several of that A/C vents in the ceiling will not turn and a couple will not open.
Anyone know how to correct this ?
Dealer tech has no clue !
2019 Isata3 FW

[hhl]

I tried to turn 2 off them by cab over bed. Broke the vents.
Called authorized Forrest River repair shop to order 2 replacements. I do not think they are made to turn all the others are not moveable either. 2018 isata 3 FW