side door issues on master

hi im getting a door warning on my dash and an audible alarm,its the side door,,the other day both side door and rear doors failed to open,its a work van i specialise in commercial waste and the load had locked both doors rendering the van useless with the load stuck,,Renault wouldnt touch it as they would damage it trying to priz door open and was told id have to get someone else to do it or do it my self,well i managed to priz the side door open and get the van back on the road and working again but the side door keeps creeping open in transit and the alarm comes back on,i stop close the door again a few miles down the road same thing happens its driving me crazy, though sounder only bleeps 30 times or so then goes silent but dash only shows door open which is annoying ,,,help