If debt collectors are calling you constantly, there is a legal way to stop them from calling you. Under the Fair Debt Collection Practices Act (FDCPA), a "third-party" debt collector is required to stop contacting you about a debt, once you send them a letter and notify them that you either no longer want to be contacted about the debt, or that you refuse to pay the debt.
There are examples of such letters on the website of the Federal Trade Commission (FTC).
If you send such a "cease communication letter," the debt collector may return your account to the creditor, who may refer your account to a different 3rd party debt collector. Then you would have to send another letter to the new debt collector. And so on, and so on.
If you become overwhelmed with your debts, or you are sued by one of your creditors, you may want to consider filing a bankruptcy case to stop the collection actions, either a chapter 7 bankruptcy to discharge your debts (if you qualify) or a chapter 13 bankruptcy to repay your debts either partially or in full.