Vodacom Reduction of Line speed

Vodacom fibre: I received an email regarding a reduction of "promotional line speed". There is no mention of the actual speed in question and other details pertaining to my agreement, so first of all the info is limited and that is per se not good enough for me. I originally signed up for 10 mbps and this is what I received. As per email I am prompted to opt for the original line speed but have to pay more???? Just another "****" to get more money from clients? Please mail me at my email address on record as preferred communication service. There is not even a reference number or account number in the email I received, so look it up from my details as supp****.