I think there are two disappointing aspects to this.

Seats do break from time to time, but when it's noted that they are defective in some way, they should get blocked for the next sector, if they can't be repaired beforehand.

That's disappointment one.

Disappointment two is how the ball was dropped totally on board, with a take it or leave it attitude and no apparent attempt by the Senior Crew Member to try and make it right before you got off.

Also, we can't just place this failure at the feet of it being a Mixed Fleet crew ex-JNB. I've also experienced shockingly bad handling of being allocated to an unacceptably defective CW seat myself at the hands of a WW crew.