Tailgate won't unlock

[amber.2]

Well its been raining here on the Gold coast for the past week and yesterday I cleaned out my Tub and the canopy and closed the tailgate and the canopy ,
Today the tailgate refuses to open ,for some reason the handle lifts up but it feels loose , also the last few times that I've closed it I've noticed that the R/H side has not closed all the way and I've had to give it a push the shut it completely ,
Any ideas ?

 

[amber.2]

I booked into Nissan and they fixed the problem , saying that a plastic clip had failed and the lever was not pulling the cables in to release the tailgate ,