The coupler issue,# 56315-2K000FFF should have no relationship with excessive play in the steering column. Yes it does feel like play when the electronic motor slams into the steering column mechanism, but a good mechanic should be able to differentiate between the two. Especially because these models are so prone to the issue. The mechanic ( I"m guessing) in the picture, Has he had a lot of these I30s through his shop? I mention this as a U.S youtuber mechanic had an elantra (U.S i30) with a steering clunk, and he replaced that u joint part and the clunk didn't go away. He was inundated with comments about the coupler needing replacement. Which he did and the clunk was fixed. What ever the outcome, I hope they can fix your car.