If the trades have been up for 7 days, they will be automatically removed if they're not accepted by anyone.
Your goods will go back into your stockpile as if you had deleted the the trades manually.
If you still believe that you are missing goods, your best bet would be to submit an in-game support ticket for the support staff to investigate. They will be able to check your logs and find any errors.
To submit a ticket, right-click anywhere in-game, then select 'Contact Support' and follow the on-screen prompts from there,
If at all possible, try to include as much info as you can, eg, what goods you think are missing and what the trades were(goods and amounts)