Uncontoctable and over debiting

I have sent sms and tried to email it call but having no luck with to get hold of them. When I try doing it via app it does not allow. I am now suddenly being charged more on my contract and not having being asked. There are months whereby I was charged more and yet I bought airtime to buy my own additional data. I am getting invoices with this new charge which includes additional data not what we agreed on.