Losing IP

I recently went on a 3 week vacation, before I went I played the heck out of Jhin while he was on rotation and was saving up to get him, I was about 100 IP off of getting him, but fell a bit short because I lost my last match before I went on vacation. Yesterday I came back and for some reason saw that my IP was at 2643, while I was just a little short of getting Jhin before I went away and he costs 6300 so I had 6200+ IP

It's quite annoying, I checked if I maybe had bought any other champions but I had not, I have used 2 of my refund tickets one of them used on Blitzcrank, which costed me 3150, which is about the IP that I lost, maybe I didn't get the IP that I was supposed to get from the refund ticket, I'm not sure.

I'd like to get an explanation on this, and if possible get my IP back as it took me quite a while to get to that amount of IP especially in solo queue as support...