If your phones and devices are financed with Next installments, no contracts, then there is no early termination fees. ETF is related to contract sale of phones which ATT stopped offering 1/8/16. Tablets and watches are still sold on contracts, Next or full price.
Does each line indicate month to month? If yes, no contract
Do any lines indicate a contract end data? If yes, then contracts for phones are $325 less $10 each completed month. Tablets have a different ETF.
Does your bill show any Next installments? If yes, you can pay off and unlock phones.