Autoresponders that accept imports?

Hey all, I know I'm usually quiet around here (busy!)

But - I am looking for various autoresponders that WILL let you import without having the whole double opt in stuff.

(No, please don't tell me about aweber).

Here's why:

I have some old customer lists (totally legit, have receipts from their purchases etc), and another older newsletter list (around 45,000 subscribers).

Our previous two servers were so bad because the guy we hosted with was constantly hacked, plus he sold hosting to spammers. On the other server, when we emailed (even though totally legit), his other client (whom he also worked part time for), would complain that WE were taking up all the server resources. (He wanted to mail his lists).

We finally left and got our own server about a year ago. But in all that past time, we had to stop our big emailings, because nothing was getting through anymore. (Our own email addresses were refusing them - eesh!)

I've not bothered over the past year and a half or more, but have been requested by some associates to go back and reconnect with our older subscribers.

Obviously I don't want spam complaints - they aren't, they're legit opt ins, but I can't upload them to Getresponse without them doing the whole double opt in thing (or thinking we're spamming when we're not).

Yes, I do know that probably 1/3 of the emails will bounce from people changing email addresses over that time. (Which raises the 'spam' issue even though its not spam, but if someone forgets or cries wolf at the drop of a hat like yahoo people are notorious for... )

Anyway - does anyone know of half decent autoresponder systems that WILL let me upload and contact these lists (while possibly cleaning them from any bounces that occur?)

I'd rather use a proper service than my own server after all the hassles we had a few years ago.