I am using Bank of America online bill-pay to send bank-issued checks to payees. When setting up a payment I can choose the " deliver by '' date. In the past the checks would always reach the payee by the " deliver by '' date ( or sometimes even earlier ). However for the past year ( or so ) the checks NEVER arrive by the " deliver by '' date but they reach the payee 1-2 business days after that date. I contacted BofA customer service on XXXX different occasions and they claimed that " everything is normal '' from their end and that the checks may be " delayed by the post office ''. Unfortunately the envelopes are not postmarked so there is no way to know when the checks are actually mailed. However ( 1 ) the BofA checks are always & consistently late by 1-2 business days ( 2 ) the checks are similarly delayed for XXXX-XXXX different payees I am in contact with and ( 3 ) all other mail seems to arrive within 1 or 2 business days from the postmark date. All these point to the conclusion that the delay is with the bank and not with the post office. It also seems that the bank misrepresents the free bill-pay service providing a " deliver by '' date that is never met, presumably as an indirect way to promote other paid-for alternatives. 
