Third Time Unlucky!? And, still NO customer care!

I purchased an ergonomic chair for my office, which was boxed and required self-assembly at home. My first build could not be completed as the machined holes were improperly aligned with the seat mounting. I disassembled the chair, repackaged what I could and returned to exchange the item. Upon completing the second chair's assembly I found that the seat was unstable, wobbled on it's axis excessively, and had an irritating noise (squeek) emanating from the tilt mechanism. I returned the fully assembled chair for a second time and decided to purchase an alternative in its place. The alternative I'd previously considered was unfortunately sold out so I had to settle for a third attempt at assembling the same chair. To my delight, the assembly proved acceptable, however, there is a minor blemish/scratch mark on the plastic and a plastic cover for a spring of the mechanism has separated from its join at one end. I simply don't have the time or energy to return the chair for a third time and am happy to tolerate the aforementioned minor problems. I estimate an hour per assembly, an hours travel, there and back, per trip and an hour in store to exchange the item. So, in essence, I sacrificed an approximate total of 6 hours of my productivity with scant consideration. I am terribly disappointed that no effort was made to compensate for my inconvenience, especially after the second instance. Surely a discount should have been offered me or perhaps a voucher to ease my mind!?