Verizon Wireless could be in trouble after the Federal Communications Commission Chairman Tom Wheeler voiced concerns over the wireless carrier's effort to cut speeds on the users who use the most data on their unlimited 4G data plans.

Wheeler said he is troubled over the company's statement, saying the FCC wants more information on whether the move is legitimate or should be curtailed before it is implemented in October.

The move will see the top 5 percent of Verizon data users on its unlimited plans -- which are no longer on offer -- have their connectivity speed drastically reduced in high-volume areas. The move aims to curb rising costs of data, the company says, and it has urged users who believe they may fall into this category to switch to a usage-based option.

But the FCC, and Wheeler, do not appear convinced.

" 'Reasonable network management' concerns the technical management of your network; it is not a loophole designed to enhance your revenue streams," said Wheeler, in a letter sent to Verizon Wireless CEO Daniel Mead on Wednesday. "It is disturbing to me that Verizon Wireless would base its 'network management' on distinctions among its customers' data plans, rather than on network architecture or technology."

The throttling move has sparked a number of concerns over existing contracts with wireless carriers. However, Tech Times has reported that Verizon does not view the move as throttling, instead, it sees it as a means of ensuring connectivity for all users in high-volume locations, such as city centers and on public transportation.

The move is dubbed "network optimization" by Verizon and has been around since 2011, but had been used only on 3G users until now. With more Verizon users on the 4G LTE network, the move aims to ensure that all its customers have access and connectivity without losing too much speed.

"Starting in October 2014, Verizon Wireless will extend its network optimization policy to the data users who: fall within the top 5 percent of data users on our network, have fulfilled their minimum contractual commitment, and are on unlimited plans using a 4G LTE device," the Verizon announcement said.

But the FCC and Wheeler are looking closely at the deal and historic precedents in the move being made by Verizon.

"I know of no past commission statement that would treat as 'reasonable network management' a decision to slow traffic to a user who has paid, after all, for 'unlimited' service," Wheeler said.