mweb has cost me major losses due to thier bad services and lack of knowledge

Mweb has costme over 300k in lost of sales, they have lost all my infomation as they host my website ect,

they debit me everymonth, but it now almost 5 months my business have not made 1 sale as they cant honor their promises,

i have been dealing with keith and every single email to him , is not productive in responding back to me. how do i go about claiming my lost from them, as they refuse to assist in who i should be dealing with