Hi and welcome.
As stated, you should be able to sort out a new contract with Vodaphone - they will just check that your account with them is up to date. It's unlikely that you would be able to move companies though.
Any insurances can be paid monthly.
You will probably find that your overtime comes under the 10% 50/50 rule. You get to keep the first 10% over and above your normal take home pay and the rest gets split 50/50 between you and your creditors. You might be able to keep some of the rest but you would have to have a very good reason to do so.
You won't be allowed to buy your kids a TV unless you can make savings from other allowances. Christmas and birthday allowances are not allowed.
You should be able to keep this account open, a savings account is an excellent place to put your contingency allowance and any small savings you can make. I doubt you will be able to continue having £25 a month deducted from your wages for savings.
If you're not happy then contact a couple of other companies - the experts that post on here come highly recommended and you can find their details under the 'Ask a Question' link on the left hand side of the page, or visit the comparison site
www.iva.com for a list of companies and ring a couple for some free advice.