Trademark opposed

Dear esteemed members 1. I had filed a trademark with the ipindiaonline and was already at final stage of approval. 2. It has been Opposed my a attorney of a big company, sighting some similarity in the name. 3. I am a small venture I don't have resource to employ a Attorney to defend my case, so have decided to abandon the matter. 4. Now however they have directly contacted me and they want me to sign an undertaking on non-judiciary stamp paper notarised pledging not to use a name which is similar to theirs. is it lawful for them to ask me to do that? Kindly guide me Thanks of you time I had filed a trademark with the ipindiaonline and was already at final stage of approval. It has been Opposed my a attorney of a big company, sighting some similarity in the name. As I am a small venture I don't have resource to employ a Attorney to defend my case, so have decided to abandon the matter. Now however they have directly contacted me and they want me to sign an undertaking