after some time, they delivered me a faulty product: i wanted to return it. it turned out they were 'peacocking' their customer service team as well as their accounts team.

i don't think it's ok to 'peacock'; it's tantamount to fraud.

if your clients are concerned that you cannot cover their requirements, you should address these concerns, not lie to them as this impedes their due diligence. if you get caught, your reputation is destroyed, and i would be surprised if there were no legal recourse.