Spectrum Charter Botnet Malware Letter In Mail

I received a random letter from, what looks like Charter Spectrum, that our modem detected advanced botnet malware. I have never had this sent before and we use iOS products. It is directing me to visit spectrum.net/security-suite. Has anyone received this? Seems random. I didnt see a notice on Spectrum Charter’s website about legitimacy of this type of letter. Appreciate any insight anyone has.