1. Normal startup legal issues (corporate form, employment law, tax, funding, IP, etc)
2. Subject matter legal issues. The subject matter you've chosen (collections) is a highly regulated activity, at the state and federal level. You need to find someone who does collections (also called debtor/creditor) to help you understand what you can and can't do. A TOS document doesn't help limit your liability to third parties - like debtors - who may gain the right to sue you if you screw up. And that's a profitable niche for some attorneys - representing debtors who want to sue creditors/collectors who don't follow the rules. Your TOS can insist that your customers indemnify you - which may turn out to be worth nothing, if the customers are insolvent/thinly capitalized.