Please can somebody help me with this

Hi there, I'm new to this and even after reading the newbie instructs link I'm still a little confused....Lets see if I'm in the right place,

Ok so June 2019 I first received a letter from a debt collection agency named DRP acting on behalf of a company named Private Parking Solutions London LTD who claim to be employed By Tescos for parking monitoring. The penalty states that I got a penalty ticket in February 2019 yet I never had a ticket nor any letter from PPS prior to all this, also the letter was sent to my mothers address of which I have not resided at for over 35 years which I found really odd and so I contacted Tescos. After speaking with Tesco head office they gave me the phone number for the company they do employ to monitor this particular Tesco express land. ( Horizon ), I contacted this Tescos parking company and they confirmed that PPS is not the monitoring parking company for Tescos and that they are and that they had never even heard of Private Parking Solutions London LTD (PPS).

I wrote a letter to DRP debt collectors, I did not put my address or contact. I advised them that the company they were representing were not working for Tescos as they claim and that I never received a ticket nor any follow up letter from the said company, I also included that I had spoken with Tesco head office and also the actual employed parking company of Tescos and that they too could contact Tescos to get the same confirmation.

A 2nd letter dated 9 July 2019 arrived today 12 July 2019 , to my mothers address again. DRP replied, thanking me for my correspondence and that this penalty has reached the collection stage thus they will no longer accept any appeal and I must pay £160 or I will be prosecuted for £1000 by a supreme court.

I contacted the employed park company of Tescos again today and again they confirmed they had never heard of the said company claiming to be working for Tescos and that I am to write to them explaining the situation and they will send me confirmation in writing that they are in fact the employed park monitoring company employed by Tescos. Perhaps I shouldn't have but I rung DRP debt collectors (withheld my number of course), I tried to reason with the chap I spoke to but he wouldn't have it and said they have photo evidence and so I must pay. I explained to him that the company that they are acting on behalf of are not even the employed company of Tescos that they are claiming to be and that I in fact never had any ticket on my window nor did I ever receive any notice or correspondence from PPS outside of these DRP letters, the chap still told me that they will be proceeding with this matter and seeking monies from me and that they would continue to contact my mothers place of residence. I feel sick to the tummy with all this, I've never had many tickets in my 38 years of driving maybe just 4 in total and I have always paid them quickly to avoid the higher charge. I cannot for the life of me understand how a debt collection agency can act on behalf of a company/person claiming to be working for a company that they are not working for which has been confirmed twice now and will be in writing shortly, just an easy phone call DRP could do but they will not make that call and instead confirm that they are still going to continue to act on behalf of whoever and pursue me for money.

My anxieties are out the roof at the idea of bailiffs attending my mums home and causing her upset more so, she is disabled and recently had major surgery ( of which I tried to explain to DRP today but they were uninterested ), These demanding letters and how they present have completely stressed my mum out and of course that means that i am now worried sick, I'm getting on a bit myself now so none of us are so physically equipped to deal with these type of problems any more to be honest.

Can anybody suggest anything that may be helpful or at least point me in a direction that I could try...many thanks.