Read your customer agreement:
"If you cancel a line of Service, or if we cancel it for good cause, during its contract term, you'll have to pay an early termination fee. Si el plazo del contrato resulta de la compra de un dispositivo avanzado después del 14 de noviembre de 2014, su cargo por cancelación prematura será de $350, el cual se reducirá por: $10 por mes en los meses 7–17, $20 por mes en los meses 18–22, $60 al concluir el mes 23, y $0 al concluir el plazo del contrato. For other contract terms entered into on or after November 14, 2014, your early termination fee will be $175, which will decline by $5 per month upon completion of months 7–17, $10 per month upon completion of months 18–22, $30 upon completion of month 23 and will be $0 upon completion of your contract term."
You have completed 20 months so your ETF would be $350 - (11 x $10) - (3 x $20) = $350 - $110 - $60 = $180. The ETF is currently $180.
