The answer to your complaint is spelled out completely on the Royal Caribbean website here.... http://www.royalcaribbean.com/contentWithHero.do?pagename=getting_on_and_off_the_ship

There is also a list of ports where tenders are commonly used. It also plainly states "If guests are unable to tender or disembark because of due to these circumstances, there will be no refund or credit for missed ports. While we recognize your disappointment, the safety of our guests and crew takes precedence.".  You must understand that transferring someone that is wheelchair bound is very difficult and dangerous when going to a tender. I recommend that for your next cruise you take a little bit of time to research if tenders are being used at any of your ports.