Taxes coincidentally causing a 3x price change right when private equity buys a company is quite unlikely. Especially since I doubt every other company has tripled their prices.

Every other carrier hasn't tripled their prices - this one unnamed and unsourced company did. You can get a $10 or $15 cellphone plan right now, so his claim is false, or that PE company has magical powers to completely outprice the otherwise competitive mobile phone market.

However, "Taxes, fees, and government surcharges make up a record-high 27.60 percent of the average wireless services bill... Since 2012, the average charge from wireless providers decreased by 29 percent, from $47.00 per line per month to $33.36 per line. However, during this same time, wireless taxes, fees, and government surcharges increased from 17.18 percent to 27.60 percent of the average bill, resulting in consumer benefits from lower wireless prices being offset by higher taxes and fees".