When the same problems keep recurring, there is something wrong (besides or in addition to) the problem you are repairing. Something has to be CAUSING the problem.
Possibility: when you replace the pump, are you also "disturbing" the grounding? In other words, disturbing it just enough to make a ground for a short time and then failing again?
Possibility: Could there be a problem in the wiring at the pump connector? Like a broken conductor inside the insulation? When you disturb it to replace the pump, you make a connection that only lasts for a short time.
Diagnostics and testing are in order here. Are you testing the pump that has appeared to have failed? Try powering it directly from the battery. If it runs, it is not failed. It is very unlikely that more than one pump in a row is bad. Something else is causing it to fail.
Could it be something in the fuel? There are additives that may be contained in fuels that could contribute to the problem. Time for some in depth investigation.