Sad customer

I've been with this bank for such a long time and Its been such a pleasure having them as my bank, but I'm very disappointed because now there's a debit order going off on my account of Ss-Legal and they can't stop it or give me any information so I can track them down, then apparently my only option is to change my account , how can my bank allow a company they don't even know to keep on deducting my account instead of just stopping them, it's so disheartening