I just had a look at your shop - all I can see on the feedback is ‘NA’ (not applicable) so I would have assumed that it just meant you hadn’t been left feedback yet, and as many buyers are ‘guests’ and can’t leave feedback that’s not really an issue.
I managed to look at a few of your items before the site decided to have a wobble. If you don’t mind taking a few tips, I would suggest doing a bit of work on your photos - it’s not my strong point either, but better photos will draw people in. Also, your descriptions lack capital letters, and are very brief. People like to buy from professional looking shops, and that means good spelling and grammar. A good description will also help, and people can’t tell much about the product otherwise, and it might put them off buying. Regarding the postage, it does seem a little high, so if you are including packaging costs in your postage charge it’s best to say so in your description. You can do one sentence that you can copy and paste into each description to cover that.
You are in probably the most saturated section for selling online - the competition is huge for selling jewellery, so you really have to make sure you stand out from the crowd to get people’s attention.