求助帮忙写封英语投诉信

a few days ago,i bought a SQ200 cell-phone at the first department store,several days later,i found that it couldn't send messages and take photoes which greatly affected my use. so i want to ask the first department store to change it for me with a new one or give back all the money i paid for the phone.

额 你得到消息的时间比我早多了啊

Dear Manager,I bought a cellphone SQ200 from the The First Department Store several days ago and found that I can't take pictures and send or receice messanges because of the malfunction of the phone.Would you please check the cellphone and replace a new one for me or refund the payment.
I hope you could deal with it as soon as possible. Your prompt reply will be highly appreciated. Best wishes,
Wang Hua