I Can't Connect To The Internet With Vodafone

I changed my phone service to Vodafone from another provider, and starting yesterday, I've been having trouble connecting to the internet on my phone. I kept getting different reasons and no solution every time I called. First, they talked about the APN settings, then they said the SIM card was faulty, and now they're saying it's my phone causing the problem (even though it was working fine before I switched to this line). In the end, I still haven't solved my problem. Dealing with customer service in real-time is another challenge. Basically, I just wanted to say thanks to Vodafone for making my first day really awful.