I want to give them business, but to no avail

I am currently on 20-gig data package at home on my landline and I've been trying for 2 weeks to actually upgrade this package. All of my calls, and there has been a few, has been directed to a number that has no answer. I've also called on various times throughout the day. It's no wonder everybody is advising me to switch service provider. To top it off I don't have a local branch within 150 kilometres that I can visit. So basically I'm stuck. Very disgruntled, actually wanted to support them.