Graham lennon

Hi am just new to forum, some interesting stuff n good advice👌🏻 So hope a can get some help🤞🏻 My car wont unlock, change battery on forbe n my key wont go in lock, only one lock on drivers door, have no clue whats wrong as all was fine last night!!! Only had car just over a month, had to do clutch flywheel n sleeve after oweing car 2 whole days!!! Now this n am scared its another expensive fix!! Any advice would be greatly appreciated, cheers lads...👍🏻