If it's very hard for sound engineer to replace a capacitor, than I really have doubts about if it really capacitor is blown.
Inspect your woofer cone by first pushing it gently back and fourth and see if you feel any bumps and ensure it moves free(that's what i would suspect to begin with). Than when you remove it from the cabinette (you may require to have either screwdriver, allen wrench or torx bit of an appropriate size) and without desoldering the woofer take a look arround.
Seriously replacing capacitor is PIECE OF CAKE and much easier than trying to get money back.
Woofer cone repair is a-bit more tricky and replacing a woofer may cost you nearly half of one speaker or more.
Inspect your woofer cone by first pushing it gently back and fourth and see if you feel any bumps and ensure it moves free(that's what i would suspect to begin with). Than when you remove it from the cabinette (you may require to have either screwdriver, allen wrench or torx bit of an appropriate size) and without desoldering the woofer take a look arround.
Seriously replacing capacitor is PIECE OF CAKE and much easier than trying to get money back.
Woofer cone repair is a-bit more tricky and replacing a woofer may cost you nearly half of one speaker or more.