Does being approved by Social Security guarantee that my private disability carrier will continue to pay benefits?

Hello. I was informed that once social security approves your claim and states that you could never return to work under the medical conditions you have and you are not at an age or physical capacity to be re-trained for future employment of any other kind. Principal or any other LTD Insurance carrier can not force you to return to work nor refuse your benefits. Is this in fact, the truth? Principal has inundated my primary care with requests every 3 months for my condition. If I can return to work. She BOLDS the NEVER portion each and every time. I find it interesting. When I first got sick and my physician stated you can not go back to work, Principal’s Representative stated to me after I placed my claim “No one ever uses this LTD” I asked “Then why do you sell it?” The other interesting fact about Principal, is that, I discovered MENTAL ILLNESS does not warrant any LTD coverage. So anyone looking to go out on LTD for any mental illness, e.g. depression etc… it’s a no win for them. They require physical limitations or disabilities. This is my impression of them. They took every penny of my retro Social Security check and then billed me for $834 more than Social Security paid me. I couldn’t win. I was sick. I had so many medical bills hanging over my head. But they won, they are the big dogs and we are nothing! They also tried to send a PI to my house to interview me, at that point I hired an attorney. Felt a PI was NOT a medical person and had no right to ask me medical questions. Felt very violated. My primary said, have them come to my office, I’ll video them interviewing you. Plus, she said she would answer all medical questions. That was some dirty works… they really tried to violate me.