Office chair - not for office use (chair broken)

First time purchase gone horribly wrong. I purchased a desk and chair from the Decopark branch. The chair had to have parts replaced from day one due to poor quality manufacture. Two months later the chair broke. I reached out to the branch who offered a repair which I declined based on the fact that the chair was clearly of inferior quality and opted to rather take a better quality chair and pay in the difference. After 2 weeks of back and forth (with no resolution) the assistant regional manager now tells me that the chair is not for commercial use (apparently an office chair should not be used for work) even though I explained that the I use the chair 3 times a week, in my home. I do not understand, how any company can sell office furniture that is not intended for work. I am currently waiting for the assistant regional manager to supply me with the terms and conditions that stipulate that the furniture is not for commercial use, with the clear definition of the same.