R.I. Gen. Laws § 39-2-1.3

No subscriber to a cellular telephone service shall be subject to an assessment of a late fee on a monthly billing unless the payment is at least thirty (30) days past the close of the billing period that is the subject of the statement. A cellular telephone operator shall not impose a late fee unless the bill contains a clear and conspicuous notice of when the late fee is to be imposed consistent with this section.