Good things to remember about … SOLVIT.
SOLVIT can help (also) with VAT refunds.
SOLVIT is a service provided by the national administration in each EU country and in Iceland, Liechtenstein and Norway. SOLVIT is free of charge. It is mainly an online service. Although there is a SOLVIT centre in each country, the best way to contact them is via the website of the European Commission: https://ec.europa.eu/solvit/what-is-solvit/index_en.htm
There are various topics SOLVIT can help with. Amongst them – the VAT refunds.
See here how SOLVIT works: https://ec.europa.eu/solvit/how-solvit-works/index_en.htm
Have a look at few examples of VAT refund problems solved via SOLVIT: https://ec.europa.eu/solvit/problems-solved/taxation/index_en.htm