Rinea review for Shippo ‑ Simplified Shipping

I have been using this app for several years and it appears that with each UI upgrade, something stops working and it never gets fixed. With latest upgrade, too much has broken and it is not longer usable - Shopify fulfillment sync does not work, order splitting does not work, Customs declarations do not import the correct information from Shopify products and it can no longer be edited, and Shopify Order sync just stopped working today. Support is very slow (by emails which takes a couple of days) and nothing gets resolved either. We are wondering if these issues are being worked urgently or if we should be looking for alternatives.