Where can you get parts for this shot gun el faisan elgobar 410 double barrel?

Best I can tell, your Spanish shotgun el faisan (the pheasant) elgoibar shotgun was made in the 1960's or 70's. I found this reference:

This import company bought the import company that imported the "El Faisan" <!--EZCODE AUTOLINK START--><a class="url" target="_blank" rel="nofollow noreferrer" href="/to/?target=http://www.tristarsportingarms.com/">www.tristarsportingarms.com/</a><!--EZCODE AUTOLINK END-->

You may be able to track parts from there.

Good luck