Corrections, bugs, and anything else.
Write to hello@theballgrid.com. It is a real, monitored mailbox and replies come from a person, not an auto-responder.
This is the most useful thing you can send, and the easiest to act on if you include three things: the date of the grid, which square (the row and the column), and the player you expected to be accepted. That is enough to check the claim against the source data and correct it if it is wrong.
There is a feedback option inside the game itself, which is the fastest route because it arrives tagged with the screen you were on. Email works just as well if you would rather.
Same address — hello@theballgrid.com.
The Ball Grid is on X, TikTok, Instagram and YouTube; the links are at the foot of every page.