Hi Shabnam, 

Most of this note is very good, and you've improved a lot in the last few weeks. The middle paragraph written in the perfect tense really sounds very strange to me. I realise you were experimenting with using the perfect tense, but it's more natural to use the simple and continuous tenses. 

A device that I've been using.

Like many people, there are a lot of devices that I use during the day. The one that I mostly use is my cellphone.
I'm not very keen on changing my cellphone every year so I have had this one for 3 years. I've been using it since then for many purposes reasons.
The first one is plainly visible: Making phone calls! I've been am able communicate easily in any place anywhere that I want.
As it's a smart phone, I've frequently been using used its other capabilities frequently.
Although When I've been home, I've never used it for surfing the Internet as much as my I've used my laptop when I was at home, but when I'm out my cellphone is the one that I've been using used it when I was out.
I have a professional SLR camera; however, it hasn't been as handy as my cellphone's camera despite of its low resolution and mid quality photos.
I'm very fond of music and when I'm on the bus, I'd like to listen to my song music collection rather than other peoples conversations. I've been using my cellphone for that purpose since the first day I bought it.
Finally I've been using it to check my favorite social app of all time; Instagram.

Please check this text, I like to fix the errors and make it more professional.