repossession of MH in TX by mortgage co for property taxes

I received yesterday, July 6th, a letter from my mortgage company stating I need to up my insurance to the "appraised market value" and provide paid tax receipt for 2010. They want the information by July 15th "to avoid acceleration of the real estate note". I sold this property on an owner finance deal in May 2009. All mortgage payments are current. I currently have the insurance at $10,000 which I have been told by the insurance is what they have as the value for this MH. The insurance company has told me to insure it for more would be a waste of my money since $10,000 is all they would pay out in the event of a natural disaster. The mortgage company is wanting me to up it to $18,816. The new owner has not paid the 2010 taxes. I know they will take care of the taxes as they did with their other property. I realize the appraisal district can reposses for delinquent taxes but can the mortgage company? and can the mortgage company reposess for my insuring for what the insurance company states is sufficient instead of what they want me to insure it for? I am not sure but I am thinking even the appraisal district would not be repossessing this soon.