Bad service

I have bought a starter for my BMW 23/03/2020. The starter breaks two weeks ago. The starter still have a guarantee of a year. Taking it back to South End Motor Spares in Strand with the slip when we bought it - they advise us that they will sent it back to the manufacturer for repairs. Now the manufacturer cannot find a bendix for the starter and we must wait. We without a car for 2 weeks now. My question is that if the manufacturer dont have the spares to fix it why selling the stock then. Should SOuth End Motor Spares give us in this instance a starter?