Hi,
I'm trying to read over your content and it just keeps loading more products. Very frustrating. You should consider pagination and having a default amount of products load on the page.
Regarding your internal links, you have one the says "2000 gifts for men" and one that says "shop gifts for men". These links point to the page the exist on, with a hashed URL. Links should never point to the same URL on which they live, I see this a lot and its very frustrating, it looks spammy to search engines, and is confusing/frustrating/irritating for searchers. They click that link only to be taken to the top of this long page again? Not a good user experience. There's also a link for your homepage buried in "..." in the first paragraph, that also looks spammy/cloaky to me.
I'm not saying these page load and internal linking issues are your whole problem, but they're definitely not helping your situation and the simplest things like this should be tackled first.
There are no external links pointing to this page, if your competitors have similar pages with some recently acquired good quality external links to them, this is potentially the cause of your recent decline.