Did you send by post or courier? You should have sent it by courier. Hopefully strike would be over soon but if it doesn't reach there before 1 July write them email that it got delayed because of unavoidable circumstances and wasn't your fault so please consider it The plea might not work since you had means of getting the documents to them but you chose the postal option. Just pray that the documents arrive on time.. But first wait and see if it reaches in time.
Thanks