Lawyers for Facebook and Instagram have given the British owner of an anti-litter app called LitterGram a deadline to confirm that he plans to change its name, he said.
Danny Lucas, 49, from Wrotham, Kent, last year decided to launch LitterGram which asks users to photograph, share and geo-tag litter they see on the streets in an effort to raise awareness and discourage litterers.
But the businessman has run into a wrangle with Facebook, which owns the photo-sharing service Instagram, which argues that the use of "gram" in the title could undermine its brand.
Facebook also contends that the use of photography and social aspects of the app are too similar to that of Instagram, which has more than 500 million users.
Mr Lucas says he has been given until Friday to confirm plans to change the name from LitterGram, which he had hoped would prove to be a revolution in combating Britain's litter problem.
Mr Lucas has previously publicly appealed to Facebook founder Mark Zuckerberg to relent, claiming the "unreasonable demand to rebrand will kill our momentum" at a time when support is building among councils and others.
Facebook has described the motivation behind LitterGram as "admirable" and said no steps had been taken to file a lawsuit against LitterGram but that it had an obligation to take reasonable measures to protect its brand.
Mr Lucas has disputed claims he was going to trademark the LitterGram app, saying that he had instead reached a compromise with Facebook to trademark bags, T-shirts, posters and other merchandise.
He said: "We are saying, 'Don't stand on us, support us'. We have got a name that's now known, some 4,000 primary schools have been sent our education animation. No-one is going to know us if we change our name."
He added: "It doesn't seem to make sense." Facebook has said it hopes to reach an agreement with Mr Lucas without going to court.