I have had the worst experience, first my router died and I was told I can do an exchange at the store I which I went and did, the store assistant cancelled my planned accidentally as he was not paying attention to what was said to him, however he apologi

I have had the worst experience, first my router died and I was told I can do an exchange at the store I which I went and did, the store assistant cancelled my planned accidentally as he was not paying attention to what was said to him, however he apologized for the mistake and gave me a new router and a new plan. I then asked him if this will affect me in anyway and I was told no and I was told that I need to pay 242 only only, the problem then started when I got a bill of 771.10 and being told that I ordered the new router which is untrue as I was there to exchange my router only as the one I owned was damaged