Verifying of supplier approved for my country

Dear Microsoft colleagues, how can I verify the approved by Microsoft supplier? The list of goods should be dispatched is the following: Microsoft Adaptive Mouse, Microsoft Adaptive Mouse Tail and Thumb Support, Microsoft Adaptive Hub, Microsoft Adaptive D-pad Button, Microsoft Adaptive Joystick Button, Microsoft Adaptive Dual Button, MS Surface Adaptive Kit, CASE FOR SURFACE GO 3 TABLETS (FOR 15 PCS) + MICROSOFT MOBILE MOUSE HOLDERS + SURFACE PEN, Netgear Nighthawk LAX20, Digital textbook Ukrainian language/literacy, 2023/2024 academic year school, 12 months - electronic, MHPSS screening module, 2023/2024 academic year school, 12 months -Electronic
The problem is that the approved for our country distributor does not understand the importation and taxation specific, and also refuses to take responsibility in case of delivery delay, etc. Generally, the correspondence with the distributor forces us to doubt the decency of a given organization. The conditions of payment - 100% prepayment, the amount of the contract exceeds 1 mln USD (country order). So we are quite confused and would like to receive the approval that the distributor was indeed verified by Microsoft; that all those colleagues from Microsoft in our communication are real 🙂 and all this story is just the lack of professionalism from the distributor's side. Hope for your prompt response!