rain special offer: false and ********* marketing?

I enquired about rainone and received an email indicating a special exclusive offer of R300 discount on my rain purchase. See below: "don't miss out on this exclusive offer! Hey D** K*****, We're excited to offer you a limited-time opportunity to save R300 on your rainone purchase. With rainone, you'll enjoy unlimited 5G home wifi, plus FREE monthly calls, data, and SMS for 2 phones. Call us toll-free at ***or visit rain.co.za to request a call, and our sales agents will get in touch promptly. " The sales agent called me to confirm my order, and I collected the modem and sim cards the same day. The next day rain deducted the normal monthly fee and the discount R300 was nowhere to be seen. I called the call center but was passed from sales to support desk and back to sales, but nobody could assist. I consider this as false and ********* marketing.