@merikas1, that usually happened if your HZE is too low so there's no clan with similar HZE as yours. It happened because the random clan works based on your HZE and it'll try to find a clan within a certain range of your HZE. See recruitment thread and apply directly instead, you may find the one suitable for you. Alternatively, you could wait a little longer to increase your HZE. Or maybe just make your own clan :)
The price of reviving mercenaries need to be tweaked. The quest reward progression is linear, while the the cost of reviving them is 10 + 1.5^lvl (according to the wiki), which mean the cost will overwhelmingly high after a certain level (It reached 3k for level 20!). Even the Transcendent one will be to costly to revive when it go past its optimum level. Moreover, the exp requirement to level up didn't change from level to level, which mean the cost of reviving will rise and rise before we have a chance to gain the advantage from the increasing reward of the current mercenaries level.