Router and VDSL issue

Damion Manager of Afrihost, I ordered a VDSL line with speeds of 20; you sent me an ADSL Router that I paid R700. I've had endless problems where the modem could not take the speeds and was an ADSL router and not VDSL. Eventually, I sent the router back, and I was told that they are not swooping it out and not giving me any credit on the router that was recommended. I am going to lose R700, and I must pay for another router of R800 Gees; that is so unfair. I was never able to use my internet properly, and I have canceled renewed my contract as I wanted a VDSL line, and I was told it was my router that was causing the problems