Lacks Customer service, website problematic

I've been trying to get a hold of this business since the 9th August.

My payment failed. I got an email from payflex and then proceeded to try to pay it via there website. It gave me an order null message and failed. I emailed Payflex immediately and sent them a video demonstrating what happens when I tried paying my instalment.

Chris answered the next day with another link but still it failed and gave me an order null message. I emailed him back to say it didn't work. Still no response.

I have since tried to get a hold of them. They don't respond to my emails and they sent me a link that doesn't work.

I refuse to pay a late fee for a website that failed me. I need this corrected and sent a link that works. I repeat I'm not paying a late payment fee for a website that failed me. It will go unpaid until they eventually notice and contact me maybe then I'll get speedy assistance.

This is now the second time complaining about this businesses lack of customer service.