Unprofessional and inconveniencing service

They are unprofessional and inconveniencing,they promised that a part of my car will arrive in 21 days after they failed to cancel my appointment in time,it's now 30 days and I have to return my courtesy car on Wednesday

Today i spoke to this very RUDE manager Johan who doesn't want to acknowledge that they are wrong because they knew on the 29 January that one part is not available and my car appointment was on the 6 February surely they had enough time to cancel my appointment but they waited for me to come on the day to tell me of rescheduling ,by that time I already paid for my courtesy car..surely that's unconvincing

My Discovery insurance advised them that they need to hire me a rental car because they inconvenienced me,the rude guy say it was not his fault but mine because I agreed on leaving my car though I knew that the part will arrive 21 days..but it's now it's 30,I've never experience such a poor,unprofessional service..not recommend it to anyone even my enemy