The best part about using Core is that they are always there for you, if needed at any time! They can be reached via email or phone call anytime to answer questions regarding your account with them as well as help resolve issues related to billing/payments etc.. I have not had an issue in over 2 years of working through their services. If something does come up during this period it's usually resolved within 24 hours by contacting customer service who then quickly gets back into contact wtih me so we know what needs fixing before anything occurs. There really isn't much else i would like from my billers; everything works great here!!