Unless your bank is totally incompetent, you almost surely agreed to be personally liable for any debts of the LLC. So you will be personally on the hook for the credit card deb.

Venmo has to issue the 1099-K under the law. You can’t get around that.

Your employees won’t get double taxed. The 1099 only means the info is being reported to the IRS. If your employees are reporting the income via their W2 and paying taxes on it, they are fine.

What does your contract say? Does it spell out late penalties? How are disputes settled in the contract? Under whose laws are the terms of the contract governed by? Late payments may be “liable for a penalty” under local laws, but whose local laws?