After how long do you report someone for stalling

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SapolNassar
I just played agaknst someone who took nearly six minutes on move nine after already playing slowly before. They then proceeded to run out of time a couple moves later. I am unsure whether or not to report them and now want to know after how long you guys report. The format was 15|10 btw
StumpyBlitzer

https://support.chess.com/article/675-what-is-stalling

Thanks