Over R35000 in debit orders but no service received

They debited our account for the total amount of R35 568.09 after we cancelled services and they removed the systems from our premises. The people we dealt with when we requested cancellation doesnt work there anymore. They charged us every month for "monitoring premises" for 27months but the premises did not even exist anymore. So in 27months they did not once go past this premises as they would have notice that there is no shop anymore. They are refusing to credit us. Even the regional manager Clair agreed with me that we were supposed to get a credit and I have an email from her stating that we will receive our credit before end of November 2019, after with another manager Wendy decided to withdraw this credit.