Hi Neha,

Walk the developers through your requirements to start with but that's probably too late for you now. Worth doing though if you think they'll do it. Have you been involved in the project the whole time? Who is testing the product? Whoever tested it shouldn't have passed it if it didn't meet requirements.

Suggest you do a traceability matrix to map requirements to product features / screens or whatever and vice versa (features /screens that don't match a requirement). Test product to make sure the features / screens etc meet the requirements. Challenge any extra features / etc.

Escalate the developers attitude to PM. You are somewhat culpable if you are on the project especially if you tested the product. 

Kimbo

They may not know they don't understand correctly.  Don't rely on written descriptions for everything unless you've both successfully worked together for quite some time and just know how much detail is needed and have good communication habits.  This is especially important if you do not share a native language.   Until then, talk to each other about the requirements until you are satisfied that they understand and only use the written form as confirmation of what was agreed in conversation.  Now, the conversation could be face-to-face but sometimes it is better that it is over some chat tool such as Slack, Skype or Google hangouts text, so that the conversation can be re-called in detail. 

If possible, have the programmer explain his understanding to someone else on the team that also understands what is needed.  Can perhaps do this as part of how you both agree on an estimate of how much work will be required.