If the bids are paused, they should be able to un-pause them whenever they want (may have been auto paused from when they run out of funds). If they cannot be unpaused, that means that the publisher may have been the one to pause the ad instead of the advertiser.
When it says max bid too low, that means that the publisher increased their minimum daily rates, which means the advertiser will need to edit their bid to adjust to a higher rate if they want their ad to continue.
When a bid is deleted, it is just removed from the system and you can no longer view specific stats for it, although the stats it contributes to advertisements/ad spaces still remain. There is no limit to the # of bids you can create.