How to catch a young filly?

i have a young filly she was brought in from the moors i had her in the stable for 7 weeks she is in the field with my shetland pony now. she has a halter on her with a rope tied to it,she was coming to the gate feeding from a bucket on the gate and we grabbed the rope then she lost the rope we managed to get her and put another rope on when we put the feed on gate she comes but wont let us catch her and pulls us through the gate she is going to cause an accident i broke my fingers trying to get her. we have caught her before walked her through heavy Traffic,brushed her clipped her done everything when we get hold of her she is brill what could we do because im thinking of stopping feeding her until she comes round because she is all ways first at the gate,i feed her pony nuts with calming powders in it. please can someone help because im thinking of getting rid but she is my little boys and good in every other way