It seems to me like the first thing you should do is to get Winbox (the dedicated program to manage Mikrotik gear) and use it instead of what you are using now (I presume browser, i.e. webfig).
https://mikrotik.com/download
One of the distinctive advantages of Winbox is that it can usually connect to a Mikrotik device through a dedicated protocol that allows to access devices via their MAC (as opposed to their IP).
In many cases (of mis-configuration) the IP may become unreachable, whist MAC access is still possible (but you need to always be careful anyway as it is relatively easy to lock oneself out of even Winbox/MAC access).
Then, follow this:
http://forum.mikrotik.com/t/forum-rules/173010/1
and post your current configurations of both the wAP ax and RB5009.