Buffalo International Logistics service

I have been continuously running and begging buffalo to please release my return so that shein can refund me. It’s been 3 months since they lost my return parcel and everytime I call them they are of no help. It’s frustrating having to run after them and beg them for my order. Every time I call them they tell me they’re investigating and it’s been 3 months now. What is frustrating the most is that in the midst of all this so called investigation they do not update me about the progress. It seems like they want me to give up on this and I unfortunately can’t because it’s a lot of money. I am even thinking of contacting my lawyers and let them be the ones to handle this because buffalo keeps on failing me. I wish we had an option to choose our courier company on shein and trust me buffalo was not going to be chosen because of their bad service .