Document everything for two week period and then take it to small claims lawyer, ask them for legalaties on pressing charges, fileing lawsuit, and civil suit. If you don't document every thing then this willl be inafective and you won't have a leg to stand on, get caller id at the store and start writeing down the numbers of incoming callers, block all unknown name unkown numbers or private numbers, do not book an appointment for someone if a number and name do not show up on caller id.
There is one more choice and I hope I explain it well. When someone calls for an appointment you will give them a quote of the total amount due for what they want. When you are getting ready to fill in the appointment book for the time you will ask the caller for a credit card number to charge $10.00 to so you can hold that appointment slot for them..Explain to them that if they do not show for the appointment the $10.00 is non refundable. If they do show for the appointment the $10.00 already charged will be applied to there bil and let them know what the final bill would be after the $10.00 deduction for the appointment fee. Hope all that made since. Some customers may get offended, some mad and violated, others will be compliant because alot of business' are doing this now. And if it is the offending spa then they will either hang up or give a false credit card number. If card number is bad then you can either cancle appointment or call back the person and ask for another card number. Also start doing appoinment reminders if you can. Make sure you get a call back number for the caller and give a call the day before or the hour before the appointment. Should help smooth things out.
Be sure to document everything, contact a lawyer, do everything legaly, if you don't you will be sorry. Try to think of where you are responsable for some of this fuede. Did you argue back with them, offend someone and not say sorry, it takes two to tango and if your business is as important to you as I believe it is then walk away from these people and do the right thing by you, they will make their own mistakes without you helping them out and you will have everything documented so how can you go wrong? GL!!!