Customer Service Contact Shopify Shipping Agent

[Redemptionstore]

Please how can I contact the customer service to shippers on shopify? Most of my parcels are shipped directly from shopify plaforms. However, these shippers, such as EVRI and DPD (in United Kingdom) have declined any responsibility for delayed, lost and damaged parcels. Evri and DPD have been told me to contact the shopify shipping agent, who supposedly, should contact them. They said, the seller/sender is a third-party and therefore thay cannot respond to my enquiries. This is very frustrating!