I booked with AMOMA (another hotel site) and now they email me a "10% off" voucher every week. The only thing is that to claim it I need to follow a link in the

I booked with AMOMA (another hotel site) and now they email me a "10% off" voucher every week. The only thing is that to claim it I need to follow a link in the email. When I follow the link, the prices of all the rooms increase, and the room price I already had open in another tab suddenly becomes "unavailable". I've also clicked the link to remove me from their mailing list half a dozen times, but they never remove me.