An Alberta separatist has doubled down in his battle against a southern town over a three-metres-tall and six-metres-wide billboard urging the province leave Canada. Cory Morgan says the sign he paid for is still standing in Taber in defiance of a letter he says the town sent earlier this month to the private owner of the billboard demanding the message be removed by Saturday.The electronic billboard, located on town land, shows the Alberta shield surrounded by the words: “Send Ottawa a Message! Choose Alberta.” Morgan says he paid roughly $1,100 for it to be up until the end of this…