Reclaiming unfair charges from Spanish Bank

Can anyone help me please?
I sold my property in Spain in 2015. I had a spanish lawyer who had power of attorney and handled the sale on my behalf.
Since then BBVA have continued to place charges on my account for Buildings Insurance and Residents Tax.
I went to the bank in Spain personally this year and they agreed to refund me the last deduction for Buildings Insurance and told me they would have to apply to the relevant department for the refund for the previous 2 years. I have heard nothing since, Whilst I was there I also submitted a copy of my passport for identification and another copy of the Title Deeds which confirmed the sale of the property.
Having gained access to my account online because I gave them a copy of my passport I have found that I have also been charged Residents Tax in the name of the new owner!
I have since emailed and called the branch - they don't respond. I have tried to open a complaint through their head office and they refer me back to the app to open a complaint. The app no longer works because it claims I have not provided a copy of my passport and so they have blocked it. The lawyer who handled the sale refuses to get involved. She does not want to waste any more time sitting in BBVA branch and advises this is the only way to get this resolved (even though it didn't work in August).
I have also realised that I have paid PPI on Mortgage Payments....
I don't know what else to do. Can anyone advise me on how best to reclaim monies, stop taxes for someone else and close the account?
At my wits end.
Thank-you.