VIP means very important person so that is a term for celebrities, politicians, etc. sometimes stores will shut down for a celebrity, however it is rare. If you are famous, you are likely a VIP regardless of spending habits. It is because of the status not the purchasing.
VIC means very important customer. You would likely know if you reached VIC status via a gift. Your SA will set up VIC experiences in other stores if they consider you at that level within LV. Then you will be treated that way not only by your SA but also when other stores are alerted within enough time, to your arrival. Allegedly, VICs can have store shut down for them though this is ulta rare.
We had some SAs on this for long ago. There is not set standard for reaching VIC status. A goid relationship with an SA can get you there quickly. Also, the spending of $25,000 (probably an old figure now) was said to get noticed within LV. It still isn't controlling but the SA said that number will get attention if there has otherwise not been any given.