Where do I download the invoice for what I paid you?

Settings → Plan & billing, under your charges — each one has its tax invoice as a PDF. It comes from ANUNZIO INTERNATIONAL FZC with the next number from the company's own invoice book, the period it covers, the amount excluding VAT, 5% VAT and the total, so your accountant can file it as-is. Set your TRN under Settings → Ordering first if you need it printed on there. Do not confuse it with your monthly statement under Reports — that one is YOUR trading, and points the other way.