With the whole digital nomad craze this questions has started popping a lot lately. The short answer is no!.
At the hostel we currently have 2 different service providers to give our guests redundancy in case one goes down, but sometimes ironically both go down as they use the same provider. The internet problem in the island, as many of the problem in Colombia, has a lot of political connotations, corruption scandals, bad management among many other things.
if you are looking to set up base in San Andres to work online while you travel, you should probably think twice, unless your work is only based on email sending and not full VoIP calls, media uploading and the such.