Access VBA MailSend Integration

My Microsoft Access database already generates customer notifications and PDF invoices, but the current Outlook-based routine fails too often. I’d like clean, well-commented VBA that switches the send function over to MailSend’s or other commercial service so every email—text body plus optional attachment—goes out reliably (about 1 000 per month). Gmail and other free services require painful authentication and we are not interested.

Here is what I need from you: a self-contained VBA module (or class) that authenticates once to MailSend, Brevo or other reliable Platform and sends single messages, accepts parameters for subject, plain-text body, file path(s) for attachments, and returns any error detail back to my calling code. The routine must work from within a standard 32-bit Access front end and avoid any pop-ups that interrupt unattended execution.

Please include a short setup guide (API key placement, required references) and a test procedure I can run to confirm delivery, attachment handling, and bounce reporting. If another commercial sender offers a smoother VBA workflow.

Deliverables
• VBA code module/class ready to import
• Step-by-step setup notes (screenshots optional)
• Simple demo form or procedure that fires both a notification and an invoice with attachment
• Brief validation checklist showing success/failure capture