Below are links that you may find helpful.

Cambridge Investment Research Inc -  https://www.cir2.com/

Useful links for information on regulation and best practices:

SIPC - Securities Investor Protection Corporation  www.SIPC.org

FINRA - Financial Industry Regulatory Authority www.FINRA.org

FINRA Broker Check - Check Credentials brokercheck.FINRA.org

SEC -  Investment Advisor Representative credential check. www.adviserinfo.sec.gov/IAPD

IRS - Internal Revenue Service www.IRS.gov

Social Security  - The United States Social Security Administration ssa.gov

Medicare   - Medicare Administration medicare.gov