請問英文婉拒信點寫? 有個客唔想約見佢唔知點寫先唔會失禮?

Dear Mr. XXX or Ms. XXX,

Thank you for your (call or email) on setting up a meeting with us. However, we are currently busy on our (project or assignment), I will contact you once we are available.

Thanks
B.rgds
XXXXX