Serving of letter to a party

Dear All,

 A Company has served a letter by speed post to a party regarding non-payment of dues.

The party has not receipted the letter; instead they have re-send the same letter to the Company ityself.

Now, my question is whether serving of official letter and its non-receipt of the same is deeded to have been served to the party itself?

Can we take any legal action for the non-receipt of the letter by the party?

Regards

Arijit