Incorrect monthly payment

I have just started a Home Basic plan for one camera. I was quoted £4.00 a month but noticed that the invoice charged me £4.99. I tried to speak to someone but did not succeed so cancelled my subscription. I tried to start the plan again to see if it would charge me the lower price but it would only allow a £4.99 renewal fee. I have spent nearly two hours trying to sort this out and as you can imagine have been thoroughly disheartened with the Ring's ponderous and unhelpful website. Could you please advise how I can have the Plan at the original quoted price of £4.00 please.