RSAweb agree to install on a specific date but have no system to organise this but charge for early installment

Ordered a new fiber installation with a specific request for installation a month later. RSAweb confirmed in writing that "We will definitely arrange for the installation to take place on the 1st of June 2019." but did not advise the fiber installers. RSAweb then got the installers to install even though I continued to advise everyone that the system only goes live a month later. RSAweb then billed me for the month but I only received the modem 2 days before end of month. Also RSAweb indicated that they do not have any way of telling the installers when to install so even though they confirmed with me RSAweb ****. I have been asking for a refund and all requests are ignored. RSAweb agreed to an installment date but are now relying on information below the agreement statement which makes me responsible for telling the installers to get off my property. Do not have a phone number for installers. An agreement is an agreement but RSAweb refuse to admit they stuffed up and have charged for a service I did not request and could not use.