Payday loan HELP

I live in the state of Texas and have multiple internet payday loans. I wanted to find out if all the loans are illegal in the state of Texas. The loans are with the following companies.

My Cash Now
Zip 19
United Cash Loans
US Fast Cash
Check n Go
Cashnet USA

I have closed my bank account so that they cannot debit anymore money from my account.

For one of the companies I have paid more than what the principal was on the loan. Could someone send a template for a letter asking that they mark my account as paid in full.

I need to find out the addresses for these companies so that I can send cease and desist letters.

Thanks for any help....