You are kidding?

This little component is a tiny part of a much larger system.  They are all broken in the decade or so old secondary glazing that came with a house.  All the glass and aluminium is fine, just the little bits of plastic are 'brock'.  Having found a company that uses them in their secondary glazing, we invited them to sell us some replacements. 'We are unable to supply you without the original job number of your installation'.  Unable?  How so - 'unable'?  Because we are unable to supply you unless we have the original job number.  Now we all know that glazing companies are shrouded in mystery, including price flatulence, and that your installer buys from a company that assembles from components that a system proprietor supplies using bespoke component manufacturers.  (Think of fleas on the back of larger fleas etc).  But to deny to supply as a genuine replacement is so odd that a rat may be smelt - but which one:  Unlicensed IP infringement?  Restraint of trade?  In the end 'Unable' became able and willing and for free.  I am still mystified as to why.  But thank you anyway.  Is there a market waiting to be exploited here for copies (or even slightly improved versions) based on 'must fit' aftermarket.  Confused: just think what would happen if car exhaust makers declined to supply you with a replacement exhaust pipe for your car. Ho Hum.