Surgical masks defects

I bought surgical masks from them in mayat a price of R700 for 50 masks! All the masks when wearing them their strings will come off! In all cases il have to use a stapler bcos i knew that you can not return them especially during this time of covid19! I wrote to them to inform them instead of taking responsibility they tell me that you only use it once(which is obvious) snd they are nit returnable What a shame!