Do you need to be registered in Switzerland for the two months you are working abroad, especially if you are not coming back?

I would suggest you de-register soon, tell the Commune you are leaving at the end of September, and simply cancel the telephones, apartment, insurances etc as and when you don't need them.

The office in Neuchâtel will give you a certificate which proves you are leaving, and you can photo copy this and post it with the resignation letters.

Not many companies will accept e-mail as a resignation, you need to write a letter, they insist on seeing your signature on some paper....!