A few things to consider;
- Did the missus ever sign a credit agreement? If not then why were they offering credit.
- Ask them for proof she received items.
- Check your credit file to see if it is having an impact.
- Don't speak to them over telephone and I'd suggest a letter to them along the following lines
If you continue to harass me by telephone, you will also be in breach of the Communications Act (2003) s.127 and I will report you to OFCOM, Trading Standards and The Office of Fair Trading, meaning that you will be liable to a substantial fine.
Have a look on the consumer action group forum as the guys on there will offer you some fantastic advice no doubt.