Hardie's Peugeot, Stirling, Scotland

On returning a Peugeot 308 to Hardie's car hire after 1 week and £250, I was treated with discourtesy and unprofessionalism. We received the car clean, slightly less than half a tank. Was requested to return with slightly less than half a tank. Slight hassle, but fine. After a week on the coast, car had some beach sand in it. But completely empty, not a water bottle or coffee cup. I did not wash or hoover the car - hotels don't lend out hoovers. This caused two employees to berate me at length. "Would I treat my own car like this? If it's someone else's car you should treat it better than your own"...they would never rent me a car again, etc. No worries there, I would rather walk. Would they treat their own customers this way? Our own car goes for servicing, clean or dirty, it comes back spotless, inside and out. This dealer and hire car location is unbelievably bad.