I really have to vent!!

I am not one that likes to air my problems, unless of course I have no answers. Well this is one of those time. I am in such a situation that I can no longer stand. It has been going on for about 15 or so years. I am less and less inclined to deal with this as time goes on. Let's just say the camel's back has now been broken. For countless years I have been dealing with a woman who believes that my eldest is her own. From the beginning I have had issues with this woman. The problem comes in because the woman is my childrens' grandmother, on their fathers side. She has been nothing but a problem since my daughter was born. Always trying to take control. I have had many issues with the gma, but she doesn't seem to get the hint. Now like I said, the camels back is now broke and I am at my wits end. This all stems from her most recent (summer visit) actions. And by this I mean, going over my head as the parent of my daughter. She blatantly did something which she had no approval from me to do. I know it may seem stupid for me to complain about this, but I know her and I know her intentions. The gma recently opened a checking account for my 15 yr old daughter. She told her that she would put money in whenever my daughter needed it. WELLL........that doesn't fly in this house when I am trying to teach my children responsibility. NOT AT ALL!!!!!!!! I spend my days at home with my kids, being a mom. I became a parent and from then on I have done nothing but live for my kids and their best interests. Now, after being away for 3 weeks with their father, they come home and as always....issues. This time its the bank account that I did not approve, but it was opened anyway. I don't spend my time devoting my life to my kids for someone to try and manipulate them right under my nose. HELL TO THE NO!!!!!!!