I empathize with your situation, as I use BofA to pay my bills as well---and while I agree it is convenient, it does come with a risk.
When we use a bank as our agent to pay our bills, we are at fault if the bank doesn't do as we direct it to do, or if the payment does not arrive.
Because this is your landlord who has not been paid, and he is sending you a 3 day pay or quit notice, I strongly advise that you pay the landlord directly and today so that you are not evicted. If you pay the rent within the 3 days, your landlord cannot evict you this time. But if there is another problem with payment in the next 12 months, then the landlord can evict you.
I'd suggest that you pay your landlord directly, and preferably in person each month from here on out and not trust the bank or the post office to deliver the check in a timely manner. Because you can't point to the bank or the post office as a defense in an eviction suit.
You may reply back to me using the Reply link and I will be happy to continue to assist you until I am able to address your concerns, to your satisfaction.
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I wish you and yours the best this holiday season,