Britannia Windows

I have you used Britannia windows from Bognor Regis branch for years I’ve had my whole house double glazed with them last year 2018 I had three other bay windows replaced at a cost of £300 I then had my back door dropped so they sent a repair guy round here just had the hinge and replaced it with a screw that he had in his van I said that was the best he could do and that they would invoice me which would be £50 I thought no more of it and 12 months later I get an invoice 12 months who is doing the bookkeeping there with the added bonus on the bottom if I didn’t pay they be sending out a debt collector now is this a way to treat someone on their own and with mental illness I am now distraught why have they waited 12 months and why they treated me like this when I’ve spent a lot of money with them instead love to them I would never recommend using this Company if this is the way they treat people it’s appalling it’s their mistake and now the penalising me for and sending me threatening letters