Call the customer service, the delivery man took back the sofa, and resew the leather by pulling it to the extreme in order to prevent the leather not to sink or enable to bounce back.

2 weeks later, the sofa was delivered to me.  However, the same issue still does not solve, but the situation become worse.  Beside the bad sewing workmanship, now the sofa become so hard to sit and uncomfortable, to the extend that my leg has blood circulation problem before 1 movie end.  Not only that, 2 big holes are obviously noticeable after the two seats are pulled out.

Now the sofa has been taken back again.  And I am not sure how they are going to rectify it?

We just moved in to this newly renovated house in less than 2 months, and already suffered the pain of sitting without sofa for about a month.  Not to mention the sad feeling of sitting on the uncomfortable sofa for about 2 weeks.