I purchased a lot with a doublewide on it.I recently had it surveyed and the property line goes two feet into doublewide.what should I do?thanks

Whose property is the other part on and what do they have to say about it?

They do not know about.our mortgage company says not to say nothing about it.what should I do?thanks:)

Well you can say nothing but start saving up money to have your double wide moved. Since when they discover it is over the line, they may be able to force you to move it.

The "right" thing to do, try and buy part of the land, or move the home to your own property.

You also may want to have the line double checked, it is unusual that a building inspector would approve a home being put incorrectly

Also check with the tax office to see who is paying the taxes on that section.
That can possibly be a loop hole in working at making a deal with the people.

They can force the move.
If you've been paying taxes on it or using it for a long time, in some states you can actually take the relevant parcel of land in court via prescriptive easement.

I'd actually keep my mouth shut about it, but the problem is, you can't rest easy. The current owner may not know or care but if he./she dies or sells the place and they have it surveyed, you're in for a world of hurt.

You cannot rely on municipal authorities for anything.
Basically all laws are written in such a way that gives them permission to annoy you however they please, but insulates them from liability for whatever they do (or, fail to do). Some counties have no involvement with the survey process whatsoever. Mine does not.