i think it's some bad algorithm. i used to be also on first 2 rows and get daily 2-5 people to contact me but now in 2 last month I made just 1 sale, quite a while no-one has contacted me! I'm level 2 seller with 1h response rate and 100% 5star rating. I don't think any of my clients have given me negative review, even if they would, 1-2 reviews wouldn't affect it so much compared to all the good reviews!
check your gigs editing pages, there might be "error" - red dot or blue box that suggest what to do, usually its description or overview sections.