"Unlimited refill" is "무한리필"(mu-han-li-pil) in Korean.
It is a compound word of 무한 (Muhan, infinite) and 리필 (refill, your place). It began with such restaurant such as coherency shop, all-you-can-drink and all-you-can-eat food and beverage outlets, but now not only in that places but has spread a mechanism to provide unlimited services in various fields. It may be referred to 무료 리필 (Mu ryo refill, free refill).