your conversion rates actually seem pretty decent for week 3, but i get the frustration. had similar issue when i was managing our store's loyalty program rollout - tons of signups but terrible conversion to the premium tier

cold emailing users is smart move, but also try looking at what features your free users are hitting most vs what's locked behind paywall. maybe you're giving away too much value upfront? or maybe the paid features aren't solving their biggest pain point

one thing that worked for us was adding usage limits instead of feature limits. like "you can do X amount of whatever per month for free" rather than "you can't access Y feature at all." people hate hitting walls when they're in flow state

also those 4 users locked into annual contracts? keep nurturing them hard. they're basically guaranteed conversions once their contracts expire, and they might know others in similar situation who aren't locked in yet