Incompetent, unreliable & a rip off

We have used Enterprise several times. When there are no problems, they are fine |(if expensive), but when things go wrong, they are absolutely appalling.

This is what happened on our most recent rental with them:
1. The small family car we reserved was not available and we had to take either an automatic or a much larger model - not ideal but fair enough I suppose.
2. The car broke down after 5 minutes - smoke filled the interior of the car, something was very badly wrong with it - dangerous!
3. This happened at 6pm when they shut for the day so we were unable to get a replacement car that evening - very inconvenient
4. The next day we only managed to get a replacement car by ringing round all of their London offices ourselves - terrible customer service.
5. We scratched the replacement car - completely our fault but it was a minor bit of paint damage.
6. We returned the car, pointed out the scrape on the door and were informed that it was borderline, but more than likely too minor to warrant a recharge - 'phew' we thought.
7. Enterprise charged us the £600 excess for the breakdown of the first car - completely outrageous.
8. They 'accidentally' deducted another £400 at the same time.
9. They ignored our complaints about this when we contacted their customer service department via their website
10. Only after we then got the BVLRA involved did we get any response, but they eventually admitted it was not our fault and refunded our money (no apology for putting us in a death trap in the first place). But they didn't refund it all at once, it came gradually, in weird amounts, each time requiring us to go back and question what on earth was going on.
11. Without warning, 2 weeks later they took another £450 from our account. It was up to us to contact them to find out what this was for. They had suddenly decided we did have to pay them for the scratch after all! Fair enough they have the right to charge us for damage, but this seems very expensive and it is my opinion that these charges are unfair. I also think companies should give you notice if this kind of charge is to be made as it could easily have put us overdrawn or interfered with our mortgage payments etc.
12. Enterprise refunded us the cost of the original car hire (£122) in acknowledgement that the whole thing had been a nightmare - the one sensible thing they did during the whole debacle.
13. We thought it was all over but then over a month after our original car hire they took another £560 out of our account without warning. Again by 'accident'! We got a refund, nearly a month later, but no compensation/interest.

So, lessons to be learnt...
1. Don't use Enterprise
2. Take out your own insurance (cheaper than through the renter) so you are not liable for any excess
3. Take photos if you do any damage to give you a better chance of disputing any rip of charges