Rain WiFi complaint and issue

Hi there I would like to complain about the rain WiFi I am very fed up as no one can help me when I call. I have had no service signal since the beginning of this month and they can’t help . I need to cancel the debit order but when I want to unsubscribe there is no option to do so and I do not want them to debit me again as I am going to another service provider .. if anyone can help me with this I appreciate it thanks