eDreams: Dishonest conditions, poor service, and rude responses

I am highly upset about the lack of transparency and consistency regarding eDreams as a booking medium. They promise services (such as cancellations or shifts) if certain fees are paid alongside the flight, but fail to deliver. They are also hard to get hold of. I booked a fully flexi return ticket through them with eDreams Prime and received an email confirming that I could shift the dates or cancel - a service for which I paid a fee that added up to 1/3 of the flight itself! However, they failed to deliver on their side of the arrangement. When I logged in and attempted to shift the flight, it stated "no additional cost" for the dates selected and shifted, pending approval (this aligned with what was paid for, asserted, and expected). However, when I received a a call from an operator (with personal service and assistance being another aspect of the additional fee promised), the price addition was suddenly required. This clashed with the nature of flight booked and paid for AND what was stated when I selected the alteration of dates on their site. I was and am unwilling to pay this. I was able to book another flight entirely for the "additional fee" that was (apparently) due to the shifting nature of flight prices. Seemingly a flight was available for what amounted to nearly 1/4 of what I would have paid in total to this service (based on the extra initial fees paid for flexibility and cancellation, the eDreams prime service, the flight itself, and the sudden "top up" fee). The do not have an email address by which they can easily be reached nor will their call line allowed you to be put through. I now desire a refund (which the service also promised). However, apparently this is an airline issue - CONTRARY to what was stated by my initial booking and the promise made to the consumer regarding both the ticket and the nature of assistance. I consider this service dishonest, unreliable, and rude. I would not recommend it.