Before you write him off completely please let me put some things in perspective. Believe me I don't who this person is but, it is not that abnormal to do one root canal in three visits. While there is more of a trend to start and finish in one visit the standard for decades is do back molars in more than one visit, often three. Even though a root canal has been completed sometimes the tooth will abscess again, this is often due to a internal fracture within the tooth itself and often dooms the tooth to extraction. It's not that common but it does happen enought to be not rare. Clindamycin is recommended by the ADA for such case if one is allergic to penicillin but Cipro is sometimes used if one is trying to avoid Clindamycin.
All I am trying to say that what you describe is pretty common and routine. That said one should always feel comfortable with the caretaker they are seeing. My patients actually enjoy seeing me. Maybe it's time to see someone else.
MyUC