DAMAGE + EXTRA OCCUPANT

Tenancy Types and Management

MY TENANT RECENTLY COMPLAINED ABOUT HER STORAGE HEATER NOT WORKING, I ASKED HER IF SHE HAD HUNG CLOTHES ON IT - AS WE HAD HAD THIS PROBLEM PREVIOUSLY - AND SHE ADAMANTLY SAID NO, AS IT SAYS ON IT NOT TO DO SO!
I CALLED IN THE ELECTRICAN AND HE SAID IT HAD OVERHEATED AND THE ONLY REASON IT WOULD DO IT, IS IF SOMETHING IS HUNG OVER IT - THE TENANT SAID TO HIM IT MUST HAVE BEEN HER SISTER.
CAN I SEND THE BILL TO THE TENANT FOR THIS CALLOUT?
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I AM CONVINCED THAT THE TENANT HAS HER SISTER LIVING WITH HER - THE SISTER IS NOT ON THE TENANCY AGREEMENT, ONLY THE TENANT & HER TEENAGE DAUGHTER IS - THERE IS MORE WEAR AND TEAR ON THE FLAT - THINGS KEEP HAVING TO BE REPAIRED - WHAT CAN I DO PLEASE?