Cardpool Pretty sure they stole my gift cards! Pleasanton California

On 4/23/18, I sold 4 $25 gift cards to them for $91.16. I used their prepaid label and followed all directions, and deposited it in the post office mailbox directly on the same day. On 4/27, I got an email thanking me for my purchase- I've heard other sellers get this email once their mail was received by Cardpool. Their site says you will get your Amazon credit in one business day once they receive the cards, but two days later I had received nothing. Since 4/27, it has said my cards are "in review." I have multiple screenshots of this as well as their turnaround promises. I have sent three emails now, and it's been almost two weeks. They outright are lying about their business efficacy and practices. When I finally got an email, they claimed to not have received my mail, and blamed USPS saying that first class mail takes 3-7 days and UP TO 3 WEEKS. What?! When I contacted USPS, they said that was a lie and first class is 1-3 days, and the only reason it would take 3 weeks is if I was sending to or from an area currently experiencing a natural disaster. USPS encouraged me to make a missing mail report to see if Cardpool did, in fact, receive the mail and are lying about it. I suspect they are as the "in review" status happened after 3 business days from mailing, and the same day they emailed me again thanking me for purchase. I also found it atrocious that the customer rep asked me for tracking information. They know da*n well their labels don't have that, and I believe the reason they don't have a number to call is because they know what they're doing and think that ignoring their customers will make the problems go away. This company is stealing from people and they are deleting comments or marking them as spam on Facebook- I have screenshots showing where my comments have been removed. I'm calling the gift card companies and checking to see if the balances were used and where, and if it's determined that a Cardpool employee took them, I'm filing a police report. I've already filed a BBB report as well, and reported it to the many military pages my family is a part of so that they can't scam anyone else as well. Absolutely disgusted with this company and I'll gladly join a lawsuit against them if available!