sounds like you have got a load of helpful BS - or put another way - agree with whatever the potential customer wants to get the order and i assume commission
as JB66 says above having booked a self install you should attempt the install - if it works great if not book a tech - as to waiting another day or two and hoping you can book one for wednesday - i dont think thats going to happen - you could ring again and change to an install if the system allows it - it may not
as to waiving fees - again thats maybe more tell you what you want to hear - if it was chat and you have it recorded then you can push but this all sounds like problems
best advice is wait for kit to arrive and attempt to install - why do you think its not going to work - if they have allowed self install then VM has been at the property before assuming you gae them the new address where the install is wanted
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Tony