I'd like your opinion on which you prefer and why. Bank or credit union?

I’ve been dissatisfied for quite a while with my bank of 30 years. Recently I overdrafted,something I haven’t done in 30 years. I have no problem with the service fee for an overdraft,as I made the mistake. I have a problem with how they handled it. The mistake was made on my account,which has my exhusband’s name on even though he’s never used it. The bank took the charges from his credit card. The bank officer said I must have verbally agreed, at some point, to have my overdraft protection covered by his credit card. My name is not on his credit card. I pointed out to her that was ridiculous as he does not use a credit card,has never used a credit card, and had not activated it. Her response was that it was okay as they activated it to get their overdraft fee. I asked why they didn’t contact me or take it from my savings acct? Her answer was that I must have verbally authorized it to be taken from my ex’s credit card. My ex was with me and he let her know how outrageous he found their action.I also talked with her superior to no satisfaction.Satisfaction would have been them admitting they made a mistake. Now I am fed up and looking at other options. Anyone care to share which they prefer, bank or credit union?