The customer service at Xchange is horrendous.
IME, the two cheapest companies for landline service I've seen so far for NYC are Selectel (it seems that they're an agent for multiple companies, but they they nevertheless seem to have cheap options) and Telzeq communications (also an agent, but I got a very cheap plan with them on Verizon, and I haven't found that anywhere else, including at Verizon themselves).
Both companies IINM are frum yidden.
They may be agents for companies that include Xchange, however the difference is that you don't have to wait on hold for an hour...
Disclosure: I am not affiliated with any of the aforementioned companies/agents, I don't know anyone from either companies, and I don't receive any commissions/referral bonuses.... My opinions are based solely on my own research, in pursuit of the cheapest plan available, and experience of being their customer.