Bulk email sending service

[bigmouk]

We need to send an e-invite on behalf of a client to around 1000 users. Last time we used 'Mail List Controller' and sent it from our mail server which was quick and easy. However, we got around 10% bounce back I think due to spam filters etc.

I need a type of PAYG service ideally as its just a one off every 6 months or so.

Any ideas ?

Thanks!!!