I am writing to express my dissatisfaction in tems of the product that I have recived a month ago

Dear Sir or Madam,
I am writing to express my dissatisfaction in tems of the product that I have recived a month ago.
A months ago I purchased a brand new gadget, which is in fact a mobile phone, from your local showroom here in Mumbai. Even though it was about a month, it started to create a number of faults such as the screen started to shut off while using and the battery was very weak and it did not last as long as it is stated in the instruction booklet. Another hing to notice is that it made strange noises while I was listening to music. To make matters worse, your employee did not respond to my early request about the faults abovementioned, but instead, he denied giving proper instruction by stating that he was so buried with work.
I am very sorry to inform about the abovementioned problems to you because I had never encountered to such situation with your company. And please change my phone into a new one or I request that you refund the money in full.
I hope you resolve the matter to our satisfaction and I am looking forward to hearing from you a kind response as soon as possible.
With regards,
Boburkhan ,