SSDA

I have been paying monthly. I got a phone call out of the blue to remind me to pay, mean while I've consistantly been paying. I asked the person how much I was still owing, I checked this amount to the last time I got the amount, whic I'd written down and the amount owing had increased. I then asked for a statement to see that they are deducting what I've been paying, was told I had to pay for an email, which I did, however I've yet to receive the statement. When I ask them to resend it they want me to pay again. They also said they were going to send an sms with the amount owing I've yet to receive this sms. I suspect they don't want me to see the statement because then I'll know that they are not deducting the amount I'm paying from my account. Why is it so difficult to get a statement.