trouble with my checking account

You may need to speak to your bank regarding this. However, if these lenders are legit in your state then you might not stand much chances against them.

Which state are you from?

I don't know about Check n' Go and Loan Point, but Summit Group is an internet lender that isn't licensed to lend in my state (I live in NY).

You need to go to your bank and speak to the manager or some other bank officer. Do not go to a teller. Explain that you got a PDL from a company you just became aware may be lending to your state's residents illegally and you want to protect the security of your bank account by putting a freeze on all debits. This may inconvenience you a bit, because if you need money you'll need to go the teller line--you won't be able to use your debit card. Also, you want to make certain that there are no authorized debits pending on your account. If so, the bank manager can allow those transactions to go through while freezing any other transaction.

After your account is secured, you want to send the illegal PDLs a email and/or certified letter stating that you revoke any all ACH authorizations to debit your account. You may want to copy your bank on this letter, so they are aware. I will tell you this, the letter is merely a formality to cover YOUR bases, because there's a good chance PDLs will NOT honor your ACH revocation. I've experienced this myself and luckily my account was frozen by then. If these PDLs have your bank info, keeping that account open is no longer an option.