Mumbai: Billionaire Anil Ambani’s battle to chip away at the Rs457 billion ($7 billion) his telecom company owes its debtors seems to get harder with each passing day.

The failure of a plan to merge with rival Aircel Ltd. to gain scale and pare borrowings has sent Reliance Communications Ltd. back to the drawing board to stitch together alternative deals to sell spectrum, land and fiber assets.

Citigroup Inc. said on Tuesday that there was now “serious doubt" about RCom’s plan to sell transmission towers to Brookfield Infrastructure Group for Rs110 billion ($1.68 billion). That deal was contingent on the merger with Aircel, Citigroup said.

Here’s a look at the company’s attempts and misses in the past decade to sell assets and share offerings.

• 2007: Ambani shares plans at company’s annual shareholder meeting to sell stakes in tower and undersea cable units to raise money for investing in network expansion.

• 2008: Reliance Infratel postponed its IPO plans due to the volatility in the Indian stock market. Parent Reliance Communications had told regulators in February that it may sell shares in the transmission-towers unit.

•2010: The wireless carrier scrapped talks to sell towers to GTL Infrastructure Ltd. after the two sides failed to agree on a deal that would have created India’s then-second largest phone tower operator. GTL had agreed to buy about 50,000 transmission towers from Reliance in exchange for cash and stock, the companies had said earlier.

• 2011: Ambani said the company is in advanced stages of selling a stake in tower firm Reliance Infratel in India’s “biggest private equity deal". Carlyle Group and Blackstone Group LP were among those said to be interested.

• 2012: Reliance Communications shelved plans for a Singapore listing of Flag Telecom saying it would “await supportive market conditions". The company was said to plan raising as much as $1.5 billion through the share sale.

• 2012: Anil Ambani told company shareholders that the tower sale may happen the following year and the company will pursue listing Flag Telecom, the undersea cable unit, in Singapore by 2014. Neither panned out.

• 2015: Talks with China’s Citic Telecom International Holdings Ltd. for sale of undersea cable assets foundered as the new management at Citic shifted priorities. The deal was said to be valued at more than $500 million.

• 2016: Talks with TPG Capital and Tillman Global Holdings LLC over sale of wireless towers, signed in December 2015, stalled over valuations. Bloomberg

Reliance Group companies have sued HT Media Ltd, Mint’s publisher, and nine others in the Bombay high court over a 2 October 2014 front-page story that they have disputed. HT Media is contesting the case.