Online service

Where do I start. I cannot log onto the website I've been trying to make a payment to for my service to be activated nobody is assisting all i want is to access my online account and make a payment so I can have wifi to work and move on with my day or understanding today they called sent a link to make a payment but the link doesn't work its seems like a **** qnd they keep saying they sent the details but I recieve nothing comon now its been 2 months its makes no sense I tried switching to a new provider and it's not allowing me too can you guy assist to urgent I'm your customer both of us will gain