While two months seems unreasonable, the fact is that six weeks have already gone by. At this point, it is unlikely that Seabourn will become insolvent in the next two weeks (and even if it did and sought bankruptcy protection, you would be covered through yout credit card). I would wait the two weeks. At eight weeks, go ahead and file a chargeback with your credit card and supply the documentation including the commitment to process a refund within 8 weeks. No reason to let it go longer than 8 weeks and it ought to all result in a temporary credit within 1-2 days and a permanent credit in short order.