BoA announces retirement on her 24th debut anniversary? ... ”Once my contract is over...” a meaningful comment

Singer BoA left a meaningful comment. On the 6th, BoA wrote on her Instagram Stories, "When my contract ends,
Is it okay to say "Untee"?
The meaningful statement quickly spread among fans and became a hot topic.
What does "contract" mean? Does "un-tae" mean "finishing sports"?
There are mixed opinions as to whether this is a difference. BoA, who debuted in 2000 with her first album "ID:PEACE B," is an artist loved not only in Korea but all over the world.
BoA has also shown her talent as an actress, but recently she has been harassed by malicious comments and expressed her distress.
Meanwhile, BoA released her new song "Emptiness" on the 26th of last month. It is her first new song in a year and four months and is a self-composed song by BoA.