Buffalo logistics disappoints

This is the second time I had trouble with getting hold of someone to help me resolve a problem. I wanted to return a parcel to Shein and due to the fact that Buffalo logistics took too long to pick up my parcel, the return date of the parcel has now expired and I can not return it anymore. I followed up twice and they said it would be escalated. After two weeks I followed up once more and they just said sorry for the inconvenience.

If it is not the client's mistake, it is Buffalo's responsibility to resolve the problem, as now I sit with a big financial loss and that is unacceptable. I would like this matter to be addressed.