fuel pump

Hello everyone, just curios I bought a after market fuel pump about 3 1/2 years ago for my 318i bmw. and does not work, removed it and doing so I found that the rubber inserts 3 of them that work like shock absorbers on the pump itself I'm guessing, where like wax melting, and the rubber was every were on pump. is this common? has anyone seen complaints about this ? any info would be appreciated ! Thanks