Awesome! This question has already 2 answers..
Yes deleting specific instances is comming soon. This is why you can already list instances, to define ID of instances that you want to remove (single or many).
For this get instance list API method may be used. Delete by instance ID API method is comming soon.
OK, I did what you asked for yesterday.
I added new API METHOD https://createproxy.com/api/cloud/delete_single_proxy/ and also in Proxy list you may find now, that if you click on Delete Button, Instance will be removed as well in your Provider Account, hope there will be not many bugs since I made lot of upgrades to make it possible.