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Calls and texts sent from my wife's mobile are often received showing my mobile number.
We both have Samsung A40 phones on Vodafone monthly contracts.
I've checked that the calls were definitely not sent from my mobile.
I've also tried to resolve this problem with customer service, but it is still happening.
The first thing to check will be the Google accounts on the phones, each phone should have a separate account with a different email address. Also, log onto the Google online accounts through gmail and make sure the accounts have the correct information for each of the numbers.
As a last resort, although inconvenient, a factory reset of the phone will clear any previous stored information and will hopefully sort out the problem.