Asking tenant to leave because of arguments before end of contact

i asked my tenant to see if he wish to continue once his contract is over which he refused. So i asked him to send me photos of house so that i can look for new tenant, but even after 7 days i did not receive any photo so i called and told them to send the photo or if they do not have time then i can send someone with their permission but they refused also refused to allow any viewings while they are still staying. basically leaving me no time to look for new tenant to which i said in that case i will deduct 1 month rent from deposit after this argument they agreed to have viewing. But right after this conversation, husband of tenant sent me message that i am harrassing them. In 7 days i sent 4 whats app messages and 2 calls lasting less than 3 mins is termed as harrassment? Now I asked them to vacate 15 days prior to official end of agreement, can i do that? With 1 month notice as per contract, Instead of 30th sept them to vacate on 15th sept. Can i do that?