The parties were locked so no new customers could join, I don't think the number of people in the party were ever locked so once a party drops below 4 people the price goes up. I was in a party of over 18,000 but I never paid attention of the number dropped at anytime. I did the upgrade in February and it went smoothly.
Since it sounds like you are still on the old Unlimited plan upgrade to the new plan to get back to paying $25 a month. You need to use the code SPRING for the discount while checking out. You will have to upgrade soon anyway since the old system/plan is shutting down at some point this year so may as well upgrade and get back to paying $25 a month.
I don't disagree but make sure the phone you are using passes the Visible compatibility checker. A number of people (myself included) have found that phones that work on the old plan will not work on the new plan.
Some phones may work that show not compatible. My G Power 2021 showed not compatible, bought a newer phone to be compliant and back in February got a card for the new phone and put it in the 2021 phone and activated and used it without issue. I didn't need a new phone but Visible told me I did. This months superuser meeting was supposed to be about this compatibility and the checker database and the main reason I attended and very little was said about it. Visible's compatibility checker and it's lack of an updated database for it is making a lot of people buy phones they don't need.
My Moto G Stylus 2021 was no compatible via the checker but I ordered the SIM using a different IMEI #. It mostly works except for WIFI calling (which is critical to me). Numerous chat sessions and second level support interventions have failed to resolve the problem. My takeaway is a non compatible phone my work but maybe not all the features.