Come on, what you said doesn't make sense, what is the relation between high connection speed and the risk of infected by ransomware? No matter your internet connection speed is 1Mbps or 100Mbps, you will get the same ransomware or any malware if you are not careful (high risk habit when just clicking next without reading when installing software, using pirated software, visiting and downloading files from non-certified website, extracting unknown zip files from unknown sources, etc...). I'm sorry but blaming the connection speed just don't make sense.

Yes. You can.
I also removed my call plan and the bill is less RM20 a month.