On the 15th of March I purchased a ticket for Paris 1 June - 3 June 2018. I check the schedule for the Train strike and the strike this scheduled for 2 -3 June which means that i wont be able to get back to Basel on the 3rd. I bought the ticket via SBB website, what can i do to get a refund or change the ticket because i cant afford to be stuck in paris until 4 June.