How do you get freeze lifted from your Experian credit report?

Please help me get access to my account. I have tried and tried using the information that I have used for years but suddenly they no longer work. I also have a pin that I have tried to use without success. I have always kept my accounts at all three credit reporting agencies LOCKED at all times. The other two continue to be locked but I can not get access to Experian because the Words and symbols that I have used for a long time no longer work and I am concerned that someone else has stolen my information. Please contact me so I can provide all my information and help me refreeze my account and keep it locked like I do for Equifax and Trans Union.