Scott Duncan
The HOLDER of the BILL ALWAYS has surety.
If there is no signature, it is NOT a BILL, nor is it an INVOICE. It is a STATEMENT of the ACCOUNT (Notice). You CONSENTED to be SURETY for that ACCOUNT when you APPLIED (Begged and signed) for hydro. Legally all they must do is give NOTICE by way of STATEMENT
If it has a signature on it, it is a BILL. If it has an ENDORSEMENT (Second Signature) it is a BILL OF EXCHANGE. The TRUSTEE is the corporation you got the BILL from.
ALL BILLS HAVE TRUSTEES.
There. Everything you need. Start there.