HOPEFULLY PEOPLE WILL READ THIS REVIEW AND NEVER RENT A CAR FROM SIXT.My husband and myself were in Maine for 2 weeks end of July 2022. Through Expedia we rented from SIXT at Boston AirPort. We took out extra insurance to the value of 350 US dollars approx. at SIXT desk when picking up the car. All was fine for a week and we then got a flat tire which my husband changed. We lost a days holiday trying to source a tyre which we eventually did in Tire Warehouse in Waterville ME. I rang customer service at SIXT and followed their instructions keeping receipt and photo of tyre. On same day as we were arriving in Belfast ME my husband thought air was coming from another tyre. Luckily there was another Tire Warehouse there and on checking all the tires there the gentleman said 2 further tyres were completely worn down and not fit for purpose and we could have been killed if we hit a wet road. Got on to customer service again and was given go ahead to replace tires and pay for them. We had photos of old and new tyres and receipts as requested. We lost another days holidays. We returned the car to Boston one week later and were given assurances that we would be refunded 524 US dollars for the 3 tyres within 10/12 working days. We also negotiated a 50% refund on our payment for car rental. We returned home to Ireland and waited and waited for refund. I will not go into details as to all the trouble we had to try to get our money. I did contact Expedia but they were not helpful either. Numerous emails, phone calls to SIXT in USA and Europe, sending copies of photos and receipts numerous times. We finally got our money 10 MONTHS LATER ON MAY 30TH 2023. However, we only got the 524 USD paid for the tyres, and not the additional 50% refund of our car rental payment.I CANNOT ENCOURAGE PEOPLE STRONGLY ENOUGH NOT TO RENT FROM THIS COMPANY AS THE WAY WE WERE TREATED WAS SO APPALING IN EVERY WAY.