Rude agent in Porto, Portugal

Hired a car for my trip in Madeira, Portugal. The battery in the key fob went flat after a week, and I had endless challenges for 3 days trying to get hold of the company, as I was unable to get into the locked car. I explained i needed a new battery for the key fob, and they sent a towtruck to tow the car away. After calls backwards and forwards, I eventually ended up speaking to an agent - Carla in Porto, Portugal - who was incredibly rude and dismissive and put the phone down on me. I eventually managed to get to a main village on the island, where I was able to buy a battery. I am appalled not only at the lack of service, and rudeness, but also at the perfunctory apology I received from the company representative after I returned the car. I was unable to use the car for 3 days, and yet there was no mention of a refund or compensation for the lost days. Carla's attitude and rudeness to me as a customer, was inexcusable. Needless to say, I won't be using or recommending Sixt.