Android set up problem identification

Need someone who understands coding and malware who can help identify source of problem when a new phone and switch to new network wiped my data on multiples devices in the home. Vodafone, Carphone Warehouse and O2 blame each other. In reality I probably did not have enough virus protection and care of details etc. Its sorted now, had to reinstall everything, new phone number etc. and better security, but it still worries mainly because I am baffled and clueless when it comes to this . I saved some downloads so probably just a small job, of hour or two of taking a look to see if you can identify anything about what went wrong - need an IT
person who understands installation/set up outputs to give me an expert view. If seems there's more to to review, no problem to make it a bigger job/ more hours