I have to ask...
What was the scenario that resulted in your having only 15 minutes on your clock in a turn-based game while your opponent was able to go days without making a move?
What your opponent did seems to be against the code of conduct:
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What is the code of conduct?
On Board Game Arena, you should not:
Run out of time on the game clock.
Leave a game in progress on purpose.
Take an unnecessary and unreasonable amount of time at the end of game in an obvious losing position.
Engage in Kingmaking: enabling another player to win on purpose while there is a better move to make for yourself.
Give some piece of information about the current game situation that disturbs the normal game flow.
Communicate with another player about the game privately (for example with an instant messenging app).
Engage in provocation / triumphalism / defeatism... anything which is not fair play.
Use an avatar that may be shocking or offensive to other players (no advertisement, no politics, ...)
Breaking these rules will affect your reputation.
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