Reel bad service NO communication

Fox telecom install fiber internet connection to my to my Guesthouse. I also use Fox Telecom to to install 3 Extenders to cover the whole premises. The original Extenders they supp**** and install, was for internal use and was not installed correctly, They did not had a ladder to install one and I had to do it myself. When I plug it in it did not work. The coverage was poor did not reach all the rooms. After a big battle and schlep, these junk extender was changed to a better quality and bigger range, They refuse to pay me back for the original junk they supp****. Only after I refuse to pay for the new once they deducted the money, I paid for junk they supp****. 10 Days ago I discovered that on of the new Extenders is not working, They refuse to send some one to fix this Extender It is still under guarantee, I send about 10 e-mails and try to call but no reaction This is reel bad services, NO communication