owner vs insured rights

I bought a policy (here in Texas) to cover my dad in 2011 when he moved in with us - I am the owner as well as beneficiary and he is the insured. He is 88 and a half now and has dementia that had gotten worse - violent, throwing food, pooped his pants when he was mad at me etc. I put him in a nursing home as my sister had said (all these years) she could not deal with him more than three-four days. Anyway, she took him out of the nursing home here and he was put in one in her town two hours away. Now I believe she has him in her home since she now can access his social security check. I had called the insurance company (Constitution life/Pennsylvania Life) January 12th to surrender the policy. They sent me the forms and I signed and sent right back with the policy. I called on Feb 10th to see what the progress was. Lady in the call room said it was missing a witness signature (which tells me they had received it all before that date). She said a new form was generated to me. On Feb 17th I get an invoice form which puzzled me since I had the premiums coming directly out of my bank so I believe she told them to stop the bank draft and send an invoice out. I called that day and they said that my sister had called them and said to stop the surrender and to send her change of beneficiary and change of ownership forms. She said I had sent a Power of Attorney for him (which I definitely did not and told her so) and that HE can change things. I thought my head was going to explode :/ When I called last November to get a cash advance the man I talked to told me (when I expressed concerns that my sister would try this very thing - that ONLY the owner can do anything. They can not even talk to her about anything and even my dad can't do anything because he is the insured and not the owner. I told the lady that was not true (about the POA). That ONLY myself as the owner can change anything. She said she stopped the forms going out to my sister. She argued and argued with me on the POA. I called again the next day and was told the same thing by another lady - that she will stop the forms. Which the previous one apparently did not. She said she would fax me the form to sign. Of course, I never got the fax after three days. Called on Monday to talk to a supervisor (something I attempted on my previous calls and was thwarted) I told the man who answered the call that I wanted a manager and needed to talk to someone who would KNOW that if I don't get what I waned that day I was going to file a complaint with the Texas Insurance Commission as well as a lawsuit. Finally got to talk to a "supervisor" and then again she started in with the POA crap. When I told her that I was going to file a complaint etc if ANYTHING gets changed she immediately faxed me the form. Finally got it faxed back after I called AGAIN to get a fax number that was not busy for over an hour.

When I called on Monday, I asked the man about my phone call on the 10th as to WHY would the lady say a witness signature was missing if they never received the surrender form then. He looked and said he could not see the form nor could he answer WHY she said that if there was not one received. Apparently, there was no need for a witness signature anyway as MY signature was all that was needed.

I am calling again today to see what the status is. HOW can I get them to understand owner vs insured?