We are in Canada (Maritimes) and 90% of our tenant pay their rent electronically (e-Transfer, PAD), we still have a few who pay by cheque and a couple who pay cash (translate: go to the bank or ATM with a deposit only bank card).  

How should I play my cards ?

Right now, I have about $6800 in credit card debt, another $6000 on a Home Depot card, and a $21,000 personal.

They have paid around $70k into a $170k mortgage over 20 years so far and have been constantly falling into credit card debit, renewing their mortage over and over.. its never ending.

I would make sure to take business cards, even if you have to order some from vistaprint that just says real estate investor.

I've never done that but I'd assume if you have separate charge cards per project, you can simply see statements from them....If you find something else that works great please let me know on this.

Welcome, I will recommend to go to local meetups and make sure you go with a lot of business cards.

However, visiting neighborhood associations, investor groups and handing out your business card will help.  

You need long term debt to make the property cash flow. a HELOC is more like a credit card, it's a revolving debt.

A credit card and automatic payment is a good idea.