Difficult to cancel

I was pressured by the sales reps in a busy street to take a look at what The Unlimited Offers only to be pushed and coerced into approving debit orders to go off on my bank account. I kept it for a few months due to not being able to cancel my order because their phone lines are always busy. They do not accept cancellations over WhatsApp and do not offer support over email. I am a receptionist and cannot make calls during work hours even though I've tried. You stay on hold for 26 minutes.

Please cancel my cover, this is ridiculous.