Wallet balance is negative temporarily

Hello, first of all thanks for the great plugin, it helped me a great deal.

Second, I have a relatively busy online store, every now and then I have issues with the wallet plugin, some users get a negative balance even though they should not be able to! Sometimes the balance is inaccurate, and gets corrected as soon as they make the next purchase.

I have made a very extensive research regarding this issue, and it isn’t “cache related” there are transactions that show an inaccurate balance in the “balance” column, but after the next transaction, the balance column gets corrected. So how do I avoid this? or at least sync the balance after each transaction.

Also, I have about 350k records in my transactions table, and I believe the site is getting slow because of this, especially when users are opening their wallet page, or the admin is doing so on the backend, how do I delete all old transactions without breaking users balance?

Thanks