Consumer rights rentoza

I have signed up for rent to own with rentoza. I have been explaining to them that they should be charging me on the last business day of the month. All they have stated is we will note the system. The bank has declined the charge and now it's costing me a fortune in bank charges. They have been charging my card since the 21st of June 2021. I have sent them screen shots of the bank charges. It's strange that they can note the system for the date of charge but can not change the date of charge. I am a consumer and this is not fair to me. I'm now sitting with a massive debt with bank and would like to know who is going to compensate me for the inconvenience and bank charges.