They refuse to assist me with my refund.

I saw a G shock watch on they're website being sold which I really liked. I then ordered the watch and made payment. After making payment Techno pro advised that they did not have the watch I wanted and they would process a refund to be paid back into my account. I provided my FNB account details which I then realized a week later that the account number I provided was incorrect as the one digit was wrong. I then made contact with techno pro to advise them of this and they said I should take this up with my bank and they cant assist. I then contacted my bank FNB and they confirmed the account number does not exist and that techno pro would still be sitting with the funds or the funds would sit with the bank that they tried to make payment from. I have tried on numerous occasions to get assistance from Techno pro and they haven't been helpful. I have made them aware of this on emails and calls and still no assistance. I went on the facebook and I was attacked by the company calling me chancer and that I was trying to **** them. Techno pro owes me about R2200.00 . The company has also painted me as a ***** on social which is defamation of my character.