I just want back what was confirmed for several months. What is wrong with that?

If I'd left the seats alone it still would be but I didn't know that because (as you say) the LH seating system showed me the seats as free for me to select.

I hope you can see how I ended up in this situation and that I just try to revert back to the initial confirmed position.

There are only 4 normal economy seats left - all single seats in different rows...