So I booked a dj and gave a $100 deposit, which I will lose and I'm fine with that. My godmother is gifting us the dj but she knows someone so we now have a new dj. According to my contract, I have to send a "certified letter" at least 4 weeks before my date as to not owe him the remaining balance. I'm not sure what a "certified letter" is or what to even put on it. Can anyone offer advice or has been through something similar and can help me? TIA 