Can not redeem Dropbox plus license key bought from Amazon

Update:

Just have the future readers of this post know my issue has been solved. It took 2 days to solve it through email communication and here was timeline:

Day 1. File a complaint like this one. Walter, Dropbox support, promptly replied me on the same day and asked for the following info, which I replied immediately:

Could you please provide us with the following information so we can troubleshoot this further?

• The name of the reseller that your purchased the license key from
• The license key (this is a 25-character code provided to you by the reseller)
• The currency used to purchase your license key

Day 2. Walter told me, "I have just sent your request to a member of my team who specializes in this kind of issue. They'll review it carefully, and get back to you as soon as possible.". In about half an hour, James, Advanced Dropbox support, replied, "I've reviewed the provided keys and have, in return provided you with one 36 month key below. This will allow you to utilize your Dropbox Plus 2TB subscription for a total of 3 years, the equivalent of the keys that you initially purchased. ". I immediately tried and the new key works! Problem solved.

Overall, I am satisfied with the response speed but feel it a little awkward to reach customer service through such forum post... Guess they want to reveal the cases so people can follow in future. However, back to my specific case, as you seen, knowing how it will happen won't help you a lot. You still need email communications to solve the issue. I still think a dedicated and direct communication between customers and CSR is more a straightforward way. Anyway, wish Dropbox can figure out a permanent solutions soon so people won't have to rely the path above to solve their issue.

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Issue:

My Dropbox Plus subscription expired today. As I did in the past few years, I tried to redeem one of the license keys that I bought in the past. To my surprise, I got the error message, "That license key has been invalidated. If you’re having trouble, please contact support". I paste a screenshot below.

I have renewed my subscription in this way for the past few years and it was always successful until this time. The license keys (I have three) that I tried today was shipped and sold by Amazon.com (not any third party vendor) in 2019. Here are more details:

Item name: "Dropbox Plus - 2 TB of Storage for 1 Year (Upgrade from Dropbox Basic 2 GB) [Online Code] "

Product page: https://www.amazon.com/dp/B07998XCJT/ref=docs-os-doi_0

I have the order numbers ready and the license codes are still viewable in Amazon Games and Software Library.

Now question is what I shall do? Customer Service Representative, please email me if you need to know these license codes and purchase evidences. I need you to convert it to new code still redeemable at this moment.

BTW, I saw similar posts in this forum. Dropbox should have figured out a solution to handle this issue rather than having customers come here and complain (no official contact). Disappointed.