The telecom department has demanded payment of Rs 39.76 billion for one time spectrum charge from Vodafone India, and a joint bank guarantee of Rs 33.42 billion before it grants final approval for the merger.
RCom said that DoT has insisted on BGs against the disputed OTSC from the company at the time it approached the government for liberalising spectrum in 800 Mhz band in December 2015.
It said the DoT demanded BG despite the matter being sub-judice.
"Not only that, the DoT has unilaterally increased the original OTSC demand, without any hearing or process, based on subsequent auction prices," RCom alleged.
The Anil Ambani led firm has alleged that OTSC dues of Vodafone are to the tune of Rs 90 billion, which is around 4 times of RCom.
Telecom tribunal TDSAT on July 3 directed DoT to return BG of Rs 20 billion to RCom.
In the letter RCom asked DoT to release its BG as per direction of TDSAT without filing any petition on this matter before the Supreme Court.
Email sent to RCom, Vodafone and DoT elicited no immediate reply on the issue.