Wrong machine returned after service

We took our Siemens automatic coffee machine in for repairs. The pump, the grinder and a valve was replaced. When we received the machine back we identified it as not ours, and pointed out that the machine we handed in had an original European OEM plug attached, whilst this one had a retrofitted SA plug. Our machine also had in excess of 8000 brews registered, and this one had less than 5000. Hirsch's contacted the repair centre and the technician insisted that he did not change the plug, and also that it was the machine we had handed in. Hirsch's then basically said we have to accept the word of the technician and take the machine. We did so under duress.