Tea stains on the rug

Last June 2010
Mom complained about tea stains on the rug.
I told her that she must have done it and forgotten.
She was adamant that it was not her.
She said it was me.  She said that I had entered her suite, made a cup of tea and then spilled it.  I kept denying and she kept insisting it was not her but I who had spilled the tea.  She wouldn't let me clean it until months later and then the stain wouldn't come out.