Poor and bad service provider

My OPPO phone is irritating me with pop up messages. I tried to contact them, they recommended adguard and blokada apps which is costing a fortune. They took me through their settings but failed. I am now stuck with a frustrating gadget. I regret why my contract was changed from Samsung to OPPO. It took only few minutes with Samsung to identify and delete the app causing pop messages. I have been trying with OPPO for the last 3 days and they failed.