Front derailleur not shifting

[Arpan30259]

I have a 21 speed (3 x 7) fat tyre cycle. The front derailleur is not shifting to 3rd gear. It's shifting plate is wobbling. I tried to compress it's rivets to tighten it but of no use. The front derailleur is attached to the bottom bracket and the parts are not available in my area....any suggestions?

 

[Arpan30259]

 

[alecstilleyedye]

if it's not shifting to the big ring then you need to tighten the cable. you may even need to replace it.

 

[Ajax Bay]

First two things to check are:
1) With the limit screws loosened off (looks like it in the image), can you push the cage across far enough by hand?
2) Confirm the outer cage plate clears the large ring.
If 'yes' and 'yes' see the person not called ' Alec' answer above.
If the FD is not functioning properly (and the OP implies that) there may be no solution other than replacement.