Income tax / death taxes complaints.I would be grateful

I would be grateful if anyone financially savvy on this forum could advise me what I can do next to obtain the substantial refund I am owed from the Spanish taxman since my husband died in Jan. 2020.  I employed a Gestoria to handle all financial affairs/taxes resulting from the death of my husband. Eventually in Sept.2021 they told me they had agreed a refund of €675 with Hacienda, due to overpayment of death taxes on my inherited property from my husband.(I already owned 50% of the house in my own name). Since then. I have received nothing. When I query it with them, they shrug their shoulders Spanish fashion, and say" you will be paid soon - with interest". Of course ,they have already been paid their fee in full by me.  I employ an accountant to make my annual income tax declaration (different person to Gestoria) and I asked him if he could politely give them a reminder of the refund and he said "better to wait patiently, it won't have any result.  and I'll have to charge you extra." What can I do, if anything, to bring pressure to bear? - they don't wait for any money I owe them. Just take it when they like.  I wonder if they are waiting for me to die - I'm 79 years old now, and I could do with it now.