I want a new rubber seal for my Helifrost 18.5 cu ft freezer?

Where can I get a new rubber seal for my chest freezer. The freezer works well but the seal leaks and ice forms between the upward opening door and the freezer. I cannot find the make of the freezer in any list of presently made freezers. HELP!! There are no freezer repairers in my locality that I know of. Desperate. Bill.doorthe