Debt Collector Harassment

I received an e-mail today (22 Oct 2018) at 10:36 claiming that I owe the SPCA Johannesburg R2 685.89. I contacted Credit Intel immediately and they asked me to confirm my date of birth, which I did.

I was told that I need to pay the account before further action is taken. I then asked what the account was for and I was told "It's for your pets". I asked which pets and was then told again "It's for your pets". I requested that an invoice be e-mailed to me and I confirmed my e-mail address. I then received an e-mail at 10:49 stating that I owed R2 711.87, another e-mail at 10:52 for R2 737.86. I rep**** to the e-mail address ********** requesting a detailed invoice and got an undeliverable message stating that the address had failed with permanent errors. And then another e-mail at 11:02 for R2 763.85.

The last time I was at the SPCA was to adopt 2 dogs in 2014 and not to use their services, so please tell me why I owe this money and why it has gone up by nearly R80 in less than half an hour?