Terrible service at pick-up location, worst car rental experience so far in the last 10 years

I'm copying my review on google to warn customers to stay away from Interrent: I highly recommend trying a different car rental service. Terrible experience picking up the car. Nearly 1 hour wait with only 3 customers in front of us before reaching the counter was just the beginning. The processing of our reservation was extremely slow and the personel (although friendly) were quite incompetent. My credit card did not work with their machine and they made me feel very bad about it, suggesting that maybe I didn't have enough funds for the >1200 euro deposit. We tried as well my partners card and again it didn't work. In the end, it worked perfectly on a different machine (which we suggested trying). We almost payed for an additional 90 euro deposit insurance because their credit card machine was not functioning. They did not appologize, only smiled and said we were lucky to avoid paying for the insurance. When we left I saw they made no move to remove the credit card machine and suspect they push customers into buying into this additional 90 euro insurance when their card "doesn't work".