T-Mobile USA and ChaCha are exchanging barbs over a reported quarter-cent charge on each standard-rate text message sent over T-Mobile’s network.

ChaCha, which operates a SMS answer service, says it will drop T-Mobile from its service if the carrier goes ahead with a rumored plan to charge $0.0025 on each text message aggregators send over its network beginning Oct. 1.

ChaCha sends between 10 percent and 12 percent of its SMS traffic over T-Mobile’s network every year, amounting to about 125 million text messages per year.

Calling the proposed fee “egregious and unacceptable,” ChaCha CEO Scott Jones said in a statement that ChaCha would shift its traffic to other carriers and platforms if T-Mobile went ahead with a so-called “Twitter tax.”

“T-Mobile is a carrier that doesn’t understand the realities of content businesses including Facebook, Twitter, ESPN and ChaCha,” Jones said.

T-Mobile declined to confirm the proposed charge, but said in a statement that “business agreements with content aggregators, including messaging fees, have been common practice in the wireless industry for years. It is not accurate to characterize these business agreements as new or simply as a price increase.”

A ChaCha spokesman disagreed with T-Mobile’s statement, saying the carrier had never before charged content aggregators a fee for every text sent over its network. The spokesman said the fee could have a steep price for websites like Facebook and Twitter, potentially costing the companies upwards of $50,000 per month.

The fee hike, if its goes ahead as planned, will not affect T-Mobile’s general subscriber base. The carrier said there are no changes to its consumer messaging or data plans.