Need legal letter written and sent

My ex partner has had my personal possessions that are family heirlooms. I have been asking for them back for one year, since we broke up. They keep making false excuses such as fiscal and regulatory set backs. They claimed they were firearms so couldn’t. They’re compression weapons(bb gun and pellet gun and other miscellaneous items) confirmed with their local mailing depots that they are 100% able to ship them with no issue. They’re constantly flying from Texas to Florida and back so I know they have funds available. I’ve shipped them all of what they’ve asked and gone out of my way to let them know when I find items of there’s and returned them posthaste. I have text message documentation to show all of this. I have no other options I can see other than sending them a legal letter. Obviously as most cases you interact with, money is an issue on my end as well due to COVID-19. Please help me to the best of your ability. All I need is one legal letter. After that, if it’s to no avail, I will pursue legal action; giving whoever takes this project first pick at being hired. I’ve chosen micro project for the first step in this. But expect to pay more if further legal action is needed.