the pump prolly has a cheap bearing in it.
they are obligated to continue to replace the pump.
they tell you when something fails of bunch of times to look for somethin else becuase quite often an overtightened belt will kill a bearing faster. scicne you have an automatic tensioner the culprit is the cheap bearing.
my advice is to get a brand new pump from the dealer or shop for another one and make sure it has a usa bearing in it or take the pump apart and press a better bearing in it (rebuild it yourself)
hth