Shares of Reliance Communications (RCom) tumbled over 12 per cent in early trade on Wednesday after the telecom department told the company and Reliance Jio Infocomm that it can’t approve their deal to trade airwaves as it does not conform to its guidelines, dealing a big blow to the Anil Ambani-owned telco’s efforts to repay creditors and avoid insolvency proceedings.

The scrip dipped 12.73 per cent to Rs 13.77 per cent in early trade, while the benchmark BSE Sensex was up over 100 points at 36,450.

The development follows Jio’s letter to the department of telecommunications (DoT), written on Friday, where it sought assurance from the government that it won’t be held liable for RCom’s past dues related to airwaves. This is not in accordance with the government’s spectrum trading norms, which stipulate the buyer is liable for dues that haven’t been recovered from the seller, according to a report by ET.

“The trading rules clearly say DoT can ask both the operators or any one of them to pay the dues. Since Jio has imposed conditions, we cannot accept it (the deal) as it goes against the guidelines,” said a senior DoT official.

Shares of the company had scaled their 52-week high of Rs 41.77 on December 29, 2017 and 52-week low of Rs 9.55 on October 29, 2018.