The 23-year-old was left out of Marussia's entire schedule for the recent Barcelona test, with the team saying only that it wanted to benefit from the "consistency" of having Max Chilton in the car for every day of running.
Razia, however, confirmed there are "conflicts" relating to his 2013 contract, because of "parties with responsibilities".
He is almost certainly confirming rumours that his sponsors have missed payment dates.
Razia was quoted on Monday as saying his management expected to "solve" the problems in "a few days", but Marussia and Force India are the only teams yet to disclose their full driver schedule for the final four-day Barcelona test.
Multiple media sources say Chilton will kick off Marussia's programme on Thursday.
Brazilian correspondent Livio Oricchio, who writes for O Estado de S.Paulo newspaper, has been chasing the story.
After arriving in Barcelona on Wednesday, he said: "I left a message on Luiz Razia's cell and got no return.
"(And) I only got the mailbox of Marussia's spokeswoman, Tracy Novak," added Oricchio. "Not a good sign.
"I have learned that there are indeed delayed payments between Razia and Marussia that prevented him from testing last week.
"Hopefully it's not the case," added Oricchio, "but it looks like it's the same now, which makes me question even more Razia's future in Formula One."
Speed Week speculated that Indian Narain Karthikeyan could now be a contender for the Marussia race seat alongside Chilton.
Other sources say Ferrari-linked Frenchman Jules Bianchi is a possibility, given Force India's reported decision to sign Adrian Sutil for 2013.