Hi Waleed! This situation sounds like my LIFE! Hahaha!! Ok, so you need help writing the three letters, yes?
- For letter #1, start off very professionally and polite. State who you are, when you bought the car, and how much you paid. Then use the next paragraph to explain the problem: the breakdown and the cost of repair. Finally, in the 3rd paragraph tell the car seller that you would like either the cost of the repair or the cost of the car (and you will return the car) Your final paragraph will be short. Wish him well, and tell him that you will contact him in 3 days if he has not contacted you.
The next letters will be more personal. The Solicitor letter will be respectful but almost personal. Tell him what happened, what you have done so far, and ask him what he might do next. The Friend letter should be much more personal. You can rant more and you can ask your friend to help you with whatever step may come next. Ask him about his family, as well, and tell him a bit about yours.