Hi vwang668! I'm so sorry that you're still waiting for these credits to start - it can take up to three bill cycles, but based on the dates you've mentioned, we should definitely be past that at this point. Unfortunately, since the Support Community is a user forum, we don't have the ability to review customer's accounts or research trade-in details here to determine where the hang-up is - but I definitely think research needs to be done, because this sounds like it's taking too long!
When we set a follow-up appointment with you for a call back, if we're not delivering on that promise, that's a problem. We should do better, and I'm so sorry we dropped the ball here. Regarding your Trade-Up promotion - if your phone met the necessary conditions (paid off in full, no physical or liquid damage, Find My iPhone/Activation Lock disabled), was shipped with an appropriate RMA label to the warehouse in PA within the 30 day timeline required, then there's no reason you should have any issues with the promotion. There is an offline team that Customer Care can work with to escalate this matter. Do you still have your RMA paperwork handy? The first step is to Contact Us with that RMA number if you've got it and have a member of our team with account access look that RMA up - from there, we can forward it on for escalation if you should be receiving monthly credits and are not. I know you haven't had a great experience reaching out for help so far, but I sincerely hope you'll give us another shot here. We don't want you missing out on reimbursement for your trade-in.