Call up their customer service and request to speak to someone in authority. Request that you do not want to be put on hold. It has worked in the past for me when I have called one of the wonderful annoying call centres that these places love. Just tell them that you have paid for the service and not received all of it. I wouldnt expect to get the entire month back however as you had a service and they are not obliged to provide the full 3mbps all the time. However the modem is your own problem. If your old one was rented then they have to replace it. If the modem that you had was yours then you have to. However I cant see them paying for it.