At a hearing, the GTCS heard Ms Buchan had given a number of interviews to the Daily Record newspaper, where she claimed she could make £50,000 per month on the site.
HMRC cited her on a list of “deliberate tax defaulters” who had purposely not paid tax bills over £25,000.
It said that she had been issued with a penalty of £25,189.28 following an investigation.
However, Ms Buchan told BBC Scotland News she planned to clear any outstanding charges once a dispute over the total amount owed was settled.
She said: “I am not avoiding paying the tax bill but I am in the process of disputing the penalty charges and the final amount owed.
“Once that is all sorted I will be clearing any tax owed.”