Whoever you called, it wasn't Mozilla support. There is no phone support for Mozilla products.

I don't know how you got infected with malware, but it's unlikely that Firefox is the cause.

You should scan your machine for malware. Try Malwarebytes Anti-Malware.

https://www.malwarebytes.org/

Mozilla does not do phone support nor do they do remote access or charge for any form of support.

You should get Firefox from mozilla.org and as updates In Firefox itself.

It sounds like it was a so called update setup .exe from website that claims you have a outdated version.

Firefox is clean of any form of malware, opensource and Free.

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

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