The 26-year-old left-back has established himself as a key figure in Rovers' march to the top of npower League One but his two-year deal at Prenton Park expires this summer.
Manager Ronnie Moore believed a deal was almost done before the player elected to change agents.
"We are speaking to Zoum's agent about a new contract," Moore told the Liverpool Echo.
"Hopefully we can get things sorted because he has been exceptional this season.
"We have been trying for some time to get things tied down with him. He has a new agent now. We were practically done with the previous agent.
"It looked like everything was going through. Now a new agent has got involved and will have to see what happens."
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