weird question about legal pdls

So I am trying to pay off a legal pdl in payments and without thinking I mailed in my payment as a check instead of a money order. Can they draft the entire amount that I owe without my consent? I feel confident that if that did happen my bank would fix it if I didn't authorize it....I guess I am a little jumpy after dealing with illegal pdls. I asked for payment arrangements in writing and they never said no (or yes they didn't respond in any way) and when I called they just told me what my balance was and that I could make payments. Hoppefully this is me being stupid and paranoid but I had to double check. Thanks!