You should try resolving issues yourself with the school.
Should you encounter a problem with a member of staff, then you should initially contact the supply organiser. If this cannot be resolved then you should either see one of the senior leadership teams or contact SupplyWell who can offer advice or contact the school on your behalf.
Remember that it is essential that all issues are followed through but that they should be done with discretion and professionalism. You may want to go back to the school. You should contact SupplyWell immediately for any serious concerns.