Recently, I received an email stating that I would be assessed an additional fee for a manuscript accepted only three days earlier if the publisher did not "hear" from me in another three days. I wrote back within two hours, asking the publisher for a fourth day to pay the charges: our department administrator was off work since it was a Saturday afternoon, and the upcoming Monday was a work holiday in my country. The publisher did not write back, but instead assessed the "late" fee less than 48 hours later (not three days). I requested clarification, and again the publisher did not respond. Although charges, especially under the "open access" models, are expected and accepted (and I have not had difficulties in the past), the assessment of late fees less than five calendar days after manuscript acceptance and contrary to timelines specified in email correspondence seems somewhat predatory. Please note, however (and this is what concerns me), that this publisher isn't an outfit from Jeffrey Beall's famous list. Has anyone had similar experiences, and what is the best response to this type of business practice?