Hi @DSB1, and welcome to our Community!
Is it a direct Dropbox payment that you’re receiving or did you initially upgrade via iTunes/Google Play?
In case you’re being billed from Dropbox, I’d recommend opening a ticket with our support team and they’ll look into this further. Here’s how you can do this (don’t forget to send me your ticket number here afterwards, and I’ll leave an internal note on your behalf).
Keep me in the loop.