Telmex Invoices - Missing

Telmex has stopped sending my invoices, without notice. A real estate rep told me that, when selling, to prove principal residence, you needed the paper invoice sent by Telmex (or certain other receipts or invoices) and not a printed out, online invoice. On the Telmex web page for "Recibo Telmex Digital" it says "En caso de que lo necesites de manera física, puedes descargarlo e imprimirlo; además, puedes usarlo como comprobante de domicilio." [Translation: you can use the printed out, online invoice as a comprobante.]  Is this printed out online "recibo" accepted by businesses and (real estate) notarios as a comprobante?

Possibly; but only if in full color.