Long story short ... Swift was supposed to headline a huge country music concert in Ottawa in August 2012 called the Capital Hoedown.
Problem is ... the promoters couldn't get their act together, and to the dismay of the Canadian country music community, the hoedown was 86'd.
So why is this Taylor's problem?
According to a new lawsuit filed in federal court in New York, Swift got all of her cash up front ... and the ticket company, which had to refund $1.8 million in tickets, thinks she should foot the bill ... since she never actually did anything. In fact, even if TS were to pay, she would still walk with $700k in profit.
But Taylor's rep tells TMZ the singer NEVER made a deal with the ticket company -- and has not yet seen the lawsuit ... which means she's not exactly rushing to fork over a $1.8 million check.
In related news, they have hoedowns in Canada?!?!?