FileWorld Charged Me After JPG Conversion Without My Consent

I used Fileworld software to convert a JPG picture and agreed to make a one-time payment of approximately £0.50 for this transaction. The £0.50 was paid yesterday. However, today I noticed a separate pending transaction of £25 taken from my Lloyds Bank account, which I did not authorize or consent to as a recurring or subscription payment. When I contacted my bank, Lloyds informed me that the £25 is currently a pending transaction and advised me to get in touch with your company to resolve the issue. I was not aware of any subscription or additional charge beyond the initial £0.50 and I did not knowingly agree to a £25 subscription. I request that the £25 pending transaction be fully refunded and that any subscription or recurring payment associated with my account be immediately cancelled so that no further charges are taken. I also ask for written confirmation that the subscription has been cancelled and that I will not be charged again.