Resolve a ISP - Bulk emailling problem

We operate a service that provides daily news services via email attachments to ships at sea. Ships at sea normally cannot browse the internet, but do have access to email. The ships subscribe to our paid service, and can elect to receive regional news editions via simple Word attachments each day. We have a web based application in beta format that will allow users to update their subscriptions, and then we will send the files out each day at a specific time to all registered users. We currently offer 14 regional news editions. We developed an application that worked on a previous ISP, but found they had pre-set limits on the number of emails that could be sent each day. This was the main problem, so we changed to a new ISP that reportedly did not set any limits. We signed up to this account and uploaded the new application. However when we tried to send emails with attachments, the attachments were not sent as Word files, zipped, but rather as code within the message body itself. (totally unreadable.) We have contacted the ISP and they have asked several questions, but my coder who initially developed it is not very proactive in liaising with them. I need someone who can resolve with the ISP to allow us to send unlimited email attachments. This is all that is required. If we find that this ISP cannot provide this, I expect you to be able to identify a company who can - or any other technically achievable solution. I will pay on completion of the site being operational with sending of email attachments correctly. The fact that it did work fine on the intial site should indicate that it may just be some configuration issue on the ISP. This needs soing soonest, and most practical bid will result in further work to develop this site further. I can provide full history and logins for the various sites to the successful bidder. Thanks Matt