Plenty of services have tiered accounts. You (SLR) act like this is impossible to accomplish.. That every user must get the same, lesser amount, even if they paid for more. Put the users that paid for 50 every 72hrs on one tier, 30 every 72hrs on a tier, and newer users that agree to spend the money for 30 every 144hrs on another tier..
There is already a sort of tier system based on subscription days. You set the accounts to 30 days, or 3 months, 6 months, 1 year, lifetime..
Do something similar for when people signed up, and what they paid you for. Add a variable for x amount of downloads per x amount of hours to the accounts. And some who bought in and invested earlier than I did should have the 50 per 72 hours that they paid for, others 30 per 72hrs if they signed up before this recent change (accounts renewing should be able to still take advantage of this if they continually renew or given the option for lifetime at this download allocation), and any new accounts after October 1, 2022 30 per 144hrs or whatever you have advertised at the time they pay.
You could also allow for upgrades, like if people want to upgrade from 30 to 50 (or more.. 100) downloads in their timeframe, you could charge an extra $200-300 (or $400-500 for 100) or something to get more profit out of the later-joining pre-paid lifers. (eventually they're going to run out of things to download at the full rate and put less load on the servers).
There's an extra revenue idea, that you can use to upgrade your infrastructure, instead of breaching your contracts with customers.
