There are a number of oddities with regards ***** ***** solicitors letter. First of all, solicitors letters are not usually delivered by SMS but that can be explained on the basis that it is the only point of contact she has for you. However, I also note that not only is the letter not signed as you say, there is no reference on the letter which indicates that the matter has not been opened as a formal client matter. In addition, I note that the owners address if that is what it is, appears in the top left-hand corner. I'm wondering whether the owner has some form of association with the firm - perhaps she works or knows somebody that does - and has either taken it upon herself to type a letter on the headed paper or someone is doing her a favour in doing so in the hope that it will intimidate you.
In any event, regardless of the provenance of the solicitors letter,given that she does not have your address, there is nothing she can do to pursue you for either the return of the tack or its value because to do that she would need your address. She could of course employ a tracing agent but there would be a fee and given the value of the tack if you are right, it would simply not be financially economical. Unless you disclose your contact details to her therefore, it is my view in practice that she has no real respect of a claim for lack of your address.
However, the above notwithstanding, from what you say, you actually paid for the tack and this being the case, belongs to you not her. The obvious weakness of course is that you do not have any form of receipt or bill of sale for the transaction but you do have evidence of the bank transfer which would need to be explained by the lady in the event of any claim in the courts.
I therefore suspect the most appropriate approach in the circumstances would be for you to consider a response by return text message reminding her that you have course paid for the tack on 25/09/15 and it belongs to you and you have no intention of sending her your property and at the same time asking her to cease and desist further contact by text message as you consider it to be harassment and will if necessary make a report to the police if the unwanted contact continues. You could end by saying that if she believes she has a claim, that she is free to pursue the matter through the courts which action you will vigourously defend and claim costs against her.
Obviously you may need to abbreviate some of the above if sending by text message! keep a copy of the message you send in the very unlikely event of any further action is taken by the lady. Most modern smartphones have the ability to block SMS messages from unwanted numbers - if yours has this function this may be a practical step to prevent further contact.
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