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Please double check your myvodafone to check your credit.
It may have been used for your refresh of tariff or mms texts etc.
A Factory Reset of your phone would in No way lose any top up credit.
Customer service on 191 or Live Chat can check your account.
As @BandOfBrothers says, there's no way that a factory data reset can have removed the credit from your account. The MyVodafone app would probably need to be re-installed, and would certainly need to refresh its connection to the Vodafone system in order to show your current account status.
Also, if you don't have a bundle which includes data, the reset might well have turned mobile data on, in which case you would be paying the standard data charge of £2 per day for 50MB - that would eat through your credit fairly fast. So check that mobile data is only switched on when you require it.
You can check your balance and allowances by calling 2345 - that gives your basic details immediately, and offers options for getting more detail of your situation.
lost credit had to do a factory reset as i couldnt send pictures as it kept telling me to go to settings about a overlay which it has never done that before and only put £10 credit 2 days before
Do you have a Big Value Bundle, or one of the Freebies? Or are you just running on standard PAYG, i.e. paying for calls, texts and data out of your credit?
I still don't really understand what can be happening, but something to do with an "overlay" sounds potentially data-heavy. Is you phone giving you a measure of your data usage?
Failing that, have you tried calling CS on 191, or using Live Chat, to see if they can give you an idea of how much data you are using? See http://www.vodafone.co.uk/contact-us/# Or looking at your itemised usage on your online account? - initially you'll be shown your out-of-bundle usage, but if you go to All Usage, then break it down to data, you should see the figures.
In order to send picture messages known as mms you need a data connection and your apn internet settings need to be right and occasionally customer service need to provision your account to be able to send picture messages.
As these do not come from your text allowance you'll be charged to send each one.