I too face this kind of problem. And this happens because of not being active on Instagram for a long time. Instagram is a platform where if you are not active then your followers may un-follow you because of not seeing any interesting thing posted by you. So, if you want to get more followers then you need to post your photos daily, like others photos and comment on others pics to get noticed by them. And one of the most thing is to choose a unique bio for your Instagram account. It will attract more and more people. There are also many people who buy Instagram Views, followers, and likes as well! So, you can also buy them but you just need to make sure that you have chosen the right site for buying them.
Richard Riddles Edited question