Although I deleted plenty of pictures, videos, Apps, etc , still not able to reduce my storage amount.

What is still taking up all of the storage? See this for some help with checking the storage.

How to check the storage on your iPhone, iPad, and iPod touch - Apple Support

If it happens that “other” is eating up large amount of storage, backing up, erasing the device and restoring the backup may help reduce that.

Apple is not preventing your files from being transferred to your laptop. Your phone and computer are not communicating and maybe something in here will help, so take a look.

If your computer doesn't recognize your iPhone, iPad, or iPod - Apple Support

I am also facing the same issue, I have deleted many photos but still the storage is full and apple is not allowing me to transfer my files to my laptop and recently it has disable the provision to show my iphone icon when i connect it to my system. Few days back when the icon is visible and i could able to transfer my photos, suddenly a pop up window will appear stating " system cannot find the device "

The above action from Apple.inc purely says that they wanted us to pay for the storage and will not allow us to transfer our personal files to our system

I am using Iphone from 2012 onwards, first purchased 4s and now having 7plus, I will never buy I phone hereafter and will not recommend to anyone.

Many of my friends are facing this issue, its is a shameful act of Apple, you should not do this to your customer.