Vauxhall Insignia dpf filter

working away from home and was driving my insigna when a warning light came on and also,i also had a loss of power i found a local vauxhall dealer and said what had happened so he took into the workshop and then told me it was dpf filter which he had changed and re programmed this was last tuesday car was going well untill this sat when came back,what i cant grasp when i rev the car the warning light goes out and all power comes back and soon as i move i lose some power and warning light comes on ,i wonder if there is a slight fuel blockage bearing in mind before last tuesday i had no hassle at all because the car does 650 miles per week any suggestions would be gratefully recived