Reluctant reeds usually indicate a gapping problem, often the gaps being too big. It can be a particular issue with double-reeded harps like yours, as the gaps for both reeds must be balanced. With the covers off look up and down the harp to see if any reeds have got egregiously different gaps to all the others. Gaps should be graded from slightly bigger for longer reeds to slightly smaller for shorter ones. You also need to look down the holes at the gapping of the blow reeds, which are the inside row, if it's blow reeds playing you up. If you've never done it before, look online for advice about reed gapping: it's quite easy to do but you don't want to be snapping reeds! Seeing videos is better than me talking you through it!