Product change and incorrect invoice

I was recently on a call with sales and was sold a 20mbs down and 10mbs up. My fibre was activated but i had not yet received my router on the date promised by vox. The kind salesman told me he will get his tech team to help me configure my old wireless router in the meantime and will NOT charge me until my actual fibre route arrives to make up for the delay. Weeks went past and not to my surprise i received a bill that INCLUDED a PRORATA after i was told this wont happen. I made over 15 calls explaining and fighting and no one helped me. The phone line was dropped multiple times when they ran out of words and email strings ended when i asked for an explination. Another week later i was emailed that my line will change from 20 down and 10 up to 20 down and 2 up and the price will not change. I agreeed to this on the product sold to me which was 20 down and 10 up. You cannot change the sevice that was discussed else i would have gone else where. I urge VOX to actualyly reach out to me, cancel my contract fetch there router and cancel my bills, i refuse to pay for a incorrect invoice and a chaned product.